Thanks for the tips. My seams appear to measure at 1/4" exactly, but the pattern said use a scant 1/4". I guess I didn't expect scant to make that much difference.
Later, I saw a post that said "scant 1/4" should be about 3/16". I had my handy dandy husband make a 3/16" guide for my machine and PRESTO! A block that measured exactly right!
I think I will give some of the stretching tips a try on my undersized blocks. They may be saved yet. And if not, I'm feeling some Christmas potholders coming on.