What size board for tourneys?

Im placing my order for Christmas.  I want to get a vinyl roll up board to take to tournaments.  What is a typical size board?

Im getting the 3.5 x 1.5 pieces.  I see 2.25 inch squares.  Is that what most people use?  That leaves a 3/8" margin around the bases of the pieces and a 3/4" distance between the bases of the pieces.  

I guess what Im asking is what is typical vs what is esthetically pleasing, all within what is legal.

Any ideas?

Dave

Don't have my rulebook with me at the moment, but check out this article which claims to know:

http://wrytestuff.com/swa416727.htm

3.5"x1.5" on 2-1/4" squares is fine.

Here's 3.5"x1.75" on 2-1/4".

and the very standard 3.75"x1.5" on 2-1/4".

20X20 for tournaments is a universal standard, anything bigger than that becomes a problem , not just for finding a table big enough to fit it but for playing on and seeing all the pieces at table level, I recently got a 22x22 and find I have to stand up and get a bird's eye view to take it all in because it's just a tad too large .

Numbers are hard. I use a siple and practical rule of thumb:

Take a king and a queen and place them on diagonally adjacent squares. Place a bishop between the royal pair. See if the bishop has any chaperoning elbow room. If not, you got  some shopping to do. Your board is crowded. Bigger is better.

I recorded a detailed video of the rule on my blog. It's quite simple and practical.

I prefer a board slightly more crowded than most people.

Conversely, most people prefer a slightly bigger board than I do.

With a 3.5" king, I would prefer 2" squares.

You would probably do better conforming to most others, assuming you have no personal preference.