Suggestion: make the blocks, then lay them out on a piece of black fabric so that it looks like they are framed. That way you can see what they would look like in frames, without having to unsew if you don't like the frames. Clear as mud I hope?
this is a good suggestion
As far as the size I change mine up. If you are going to use it yourself or give as gift or sell - I would think about that. My son is tall (6'4") so the quilt I made for our couch is long to give him more coverage.. just something to think about