Ina, one thing I have found that makes a BIG difference in making your seams match is "Ironing" . I iron each block as I go, after every seam I sew, so when I'm ready to put a block together I butt the seams up to each other and I don't even have to pin. I do check to make sure they are together by wiggling them, but no pins. Of course, sometimes you have a few that just won't cooperate & then I pin. But I made 4 sets of 20 blocks of nine patch and didn't pin. They came out pretty good. I even had one of the ladies in my quilt group look at them & she said I did well....she's a home ec teacher. So I was proud. But I swear the key is to always IRON first to set your seams, then press them to one side or the other. I read that in a Better Homes & Garden Quilt Book & it really works. Try it, you'll like it....LOL The 2 prong pin sounds good too.