Is there a rule of thumb about the size of quilt blocks vs. the size of the quilt. i.e. to me 12" blocks seem to be disproportionate to a twin size qilt. Wouldn't 10" or even 8" blocks be better?

I used 12" blocks on a Twin Size and I don't think it looked disproportionate at all. I guess it just personal preference.

You can use whatever size blocks you think would look good.

I like to use smaller blocks in small quilts. Bigger blocks in big quilts. For example I have been working on a quilt for my husband that is 98x112, the blocks are 14 inches each. They look fine. Where as I would NEVER make a twin quilt with this size block.

I made a lap quilt using 12 inch blocks once. I hate it. The size of the block looks disproportionate to me.

I'm not fond of square quilts either. They gotta be oblong.

Make them any size you want, it's your quilt!
Hi and welcome from the sunny state of Florida!!

I have made 4" blocks for a 60 X 72" quilt, and I have used 12" blocks... I think it all depends on what YOU want to do :D:D:D

Welcome to the Board from Louisiana!

I also think it's up to you. What appeals to one doesn't appeal to another. The rules for quilting are not very strict!
The one rule I try to follow is HAVE FUN :)

I like the look of the smaller blocks. For example, I'm doing a quilt for my fil that's a modified sawtooth. Well if I did the 12" I wouldn't have as much of a design for the top of the bed. The 8" gave me the look I wanted, so that's what I ended up going with.

It's your quilt make the blocks as large or small as you like. :thumbup:

Dito on this and welcome to the board from Germany.