I think you need two or more boards. The piatgorsky will likely appear cramped on even 2.25. I suggest the 1.75 because you'll use it more and consider HoS clearance boards for 2.25 and 2.5 boards that you could use occasionally for the larger sets.
Drueke Board - 1.75" vs 2.25"

I would go for the 1.75" board, just because it would be used more (as you state).
The fact that your wife joins you in using the Smyslova set gives bonus points to the smaller board.

Chess Set Sizing - Pieces vs Board...
The primary sizing criteria for the pieces vs board is that of square size vs King base diameter...
A good rule of thumb is...
King base diameter = 0.75 * square size
or equivalently....
Square size = 1.33 * King base diameter
Any variation from these ratios, or the size of individual pieces and pawns, becomes a matter of personal preference...
https://blog.chesshouse.com/how-to-select-the-right-size-chessboard-for-pieces/
See also...
https://www.chess.com/forum/view/chess-equipment/a-system-for-sizing-chess-pieces-and-boards-long
You might also want to consult the FIDE Manual, Sections 2 and 3 on equipment regulations...
https://www.fide.com/FIDE/handbook/Standards_of_Chess_Equipment_and_tournament_venue.pdf
You might also want to check out these makers of custom solid wood chess boards on ETSY.com...they are good quality at reasonable prices.....they also make boards in Drueke style. Both makers have received positive reviews in the Chess.com forums...
ColoradoWoodWorker (USA)...
https://www.etsy.com/shop/ColoradoWoodWorker?ref=shop-header-name&listing_id=1595374476&from_page=listing
SakisTsiogkasWood (Greece)...
https://www.etsy.com/shop/SakisTsiogkasWood
I purchased the Brazilian cherry/Maple/Walnut board with 2.25 inch squares from ColoradoWoodWorker (Brad Borkowski)....there is a discussion of my board, with photos, starting at post #62 of this forum thread. I also posted photos of my Drueke board (2.25in squares) with the GM Blitz pieces (from ChessBazaar.com) in posts# 33-36...
https://www.chess.com/forum/view/chess-equipment/cb-gm-blitz-set?page=4

Hey @felonet - three wonderful sets… deserve two wonderful boards … you may only want one but … you need too!😆😉. I’m in the small board camp. It works for the majority of times you and your wife play and display. Further, portability is great if you ever drop down to your local pub or cafe. Finally, space on the board seems a modern’ish phenomena… many vintage photos shows boards that are far more cramped than we use today … and I, kinda like cramped now. Cramped pieces may not fit competition specs or modern tastes but vintage style works too.
I'm with Powder....Nothing wrong with a bit of cramping, unless it's my warm up pants being too tight.

I feel like your brain is saying 2.25”, but your heart is saying 1.75”. I’d follow the latter, get more use out of it, all while having a dedicated table/board combination you will enjoy with your wife. I don’t want to be an enabler of our madness, but you can always get a 2.25” further down the road! If you’re not dead-set on the local purchase, perhaps opt for a 2.25” borderless board, which comes out to the exact dimensions (18” x 18”) as the Drueke 1.75”.

Different sized sets need different sized boards, so if you have multiple sized sets it’s not really practical to only have one board. Practically speaking and based on what set you say you use, it sounds like the 1.75” would get the most use by you now.
From a perspective purely on the boards, the 2.25” Drueke is probably THE most desirable Drueke board. They are not as common as the 2” and smaller boards. If the price is reasonable and it’s in good vintage shape (scratches are easily improved with some oil), that is what I would pick up. 1.75” boards are much easier to find for not too much money.

More often than not, I've regretted passing up opportunities when they presented themselves. I'd get the 2.25" as well, you can't go wrong with a tournament sized board like that.

My wife and I almost exclusively use the Smyslova for games at home.
Seeing as you and the wife play with the Jacobson Smyslova chessmen the most over the other sets, I think you'll be happiest with a board that matches the Jacobson first and foremost. I wouldn't base the purchase of a 1.75" board just becuase it's for sale locally. Size/fit is subjective. If you've been using a 1.75" board all this time with the Jacobson and you both like the fit, go for it!
In roll-up boards, I have 2.25, 2.125, 2.0, 1.875 and 1.65 (they were all cheap on sale. A few of them I purchased as "filler" to get me over the minimum amount for free shipping on an order. Hah. These cheap roll-up boards are handy when ordering a custom wood board to test for size.

Why not go for a Custom chessboard with different size squares on both sides, if you want only one board.
Let’s say a 18 inch chessboard which is frameless on one side, so square size is 2.25 inch. Other side could be 1.75” square with a border. Only issue is if such an idea can be implemented, board will be really thick. This is not a practical solution at all, two boards are always a better option. You will buy more chess sets in future so a standard 55 mm board is a must buy.
Maybe you could talk with Brad from Colorado Wood Worker. He has developed some very interesting chessboards in the past.

In the end it's a luxury problem / the Drueke Board looks like a very fine board . Most chess players have boards in different sizes , To keep your cost down , can get always keep using the vinyl ones ! + buy both pending on price or get a bigger table ? My main board is now a rare 60 mm sq Jaques style one from the 50's . from a defunct chess club . With a bit of TLC / one of my best chess buys for 20 euros , which fit's my bigger sets just right .

@ lighthouse - Very nice board. I’ve bought/refinished-refurbished/sold a fair number of boards. With patience, good boards come up at a low cost and some will prove, occasionally very unexpectedly, to be keepers! Brad (Colorado Woodworker) is also well worth contacting.
Here are a few of my refurbished ones:
1.75” - Quite old, but worm holes and wear just added to its beauty once cleaned up. This size is too small for my favorite sets, but it’s always a joy nevertheless. I had posted it on ebay (my wife’s demand). I was thrilled that it didn’t sell! 😁
This one was a huge surprise - big (2.5”), gorgeous wood, and heavy! It cleaned up beautifully and became a ‘surprise keeper’ like the previous board.
I’ve bought and refinished a lot of Drueke boards. They’re so well made that even when in dismal condition (including damaged), they are well worth restoring. I kept this one (2.25”) and use it often.
Sorry to hijack the thread - which my been irrelevant at this point anyway - but I’m just saying that with patience and a little ‘sweat equity’ it’s realistic to acquire nice boards, especially in the 1.75”-2.25” range.

Thank you everyone for the great feedback - and never worry about hijacking my thread with pictures like that! Very nice.
The deed has been done. I have purchased the 1.75" board and I will be posting pictures in the next day or so when the lighting is just right!

@ lighthouse - Very nice board. I’ve bought/refinished-refurbished/sold a fair number of boards. With patience, good boards come up at a low cost and some will prove, occasionally very unexpectedly, to be keepers! Brad (Colorado Woodworker) is also well worth contacting.
Here are a few of my refurbished ones:
1.75” - Quite old, but worm holes and wear just added to its beauty once cleaned up. This size is too small for my favorite sets, but it’s always a joy nevertheless. I had posted it on ebay (my wife’s demand). I was thrilled that it didn’t sell! 😁
This one was a huge surprise - big (2.5”), gorgeous wood, and heavy! It cleaned up beautifully and became a ‘surprise keeper’ like the previous board.
I’ve bought and refinished a lot of Drueke boards. They’re so well made that even when in dismal condition (including damaged), they are well worth restoring. I kept this one (2.25”) and use it often.
Sorry to hijack the thread - which my been irrelevant at this point anyway - but I’m just saying that with patience and a little ‘sweat equity’ it’s realistic to acquire nice boards, especially in the 1.75”-2.25” range.
baudouin27 Some TLC + gentle hands can do wonders , Keep up the good work , Nice boards .
Good luck felonet. You should really be happy with such a treasure.
I wanted to get a larger Drueke board a while back, to go with the S.C. Ceska K set I had received at the time...but...MCH had sent me a link where I could get a 2.25" square JLP board at half price.
I took a chance and ordered it. Surprisingly, it was in as new condition. Gorgeous piece of workmanship that it is, it still doesn't have that old style patina that "comes with age".
From a personal stand point, I myself do, so the wife says.

Here we are! With the sun breaking through the window in the morning. You can certainly see this board has seen some abuse - but I don't care - I love how it looks.
Incidentally the patina is not so visible on this board. The 2.25" board had better patina but I went with the smaller board for many of the reasons posted above.
Looking for opinions. Diary of a mad-chess-collector-type-post incoming. There are two Drueke boards at my local chess club available for purchase - I would like to buy one of them but I can't decide which. My chess sets are as follows:
I have a small table which I'd like to use for playing - the 1.75" board would work nicely here. However the only set which really works on this size is the Smyslova - everything else is too cramped (especially the Piatigorsky).
To cover all bases I should buy the larger board - but it's a large and unwieldy size and cannot fit on my small table. I would have to drag it out from time to time and clear space on my dining room table - which would probably limit it's overall use in the long run.
Does anyone have any thoughts? Both of these boards have beautiful patina and up to this point I have only ever used the cheap vinyl boards. I don't want to start collecting chess boards so I really wish to buy once. My wife and I almost exclusively use the Smyslova for games at home. But it makes no sense to exclude my other sets either...
Argh!