What are your opinions of the size of a boards' squares versus the king height?

To me a typically proportioned 3 3/4" king is perfect on a 2.25" square. 

What do you think the square sizes should be if a king is 2.5", 3", and 3.5" tall?

I'm considering making some boards... 

i prefer a 3 7/8" on a 2.5" square. but that is just me.

i have seen 3.25" king on 2" squares and that is OK, but much smaller than 2" square and i'm uninterested.

don't forget base width.  I think for some sets that can be an issue for going up a square size.

If the pieces are all proprtional to one anouther then the square size should hold four pawns.  Or so i have heard.

My favorite set has a 3 3/4" king and 2.25" squares. And yes, four pawns fit snugly inside each square so perhaps that is a good guideline.