The perfect 1/4 inch seam continues to elude me, and I have been quoting for years. I also find when I press the blocks go out of square. You might try using starch or Best Press to keep them in line. But I think you still have to square the blocks up to the smallest one. Hopefully with practice they will get closer to being the same size, but I find it is easier and less stressful if I just embrace the differences. It is hand made.