The seams in the first quilt were not "exactly" 1/4 inch all over. I thought they were, but when I put it together I realized they were not. I also didn't square the blocks because I didn't know about that. in my typical fashion I just dived right in. Fortunately, I really wasn't a sandwiched quilt with batting. I live in Las Vegas and wanted something very lightweight for the spring and fall. The summers are so hot here we just use a sheet. But I liked the bed covered. So I just sewed a backing fabric to it and added some decorative stitches here and there and it serves the purpose.
I am afraid I also didn't know about how close the quilting stitched needed to be when I did the second quilt. I used Hobbs batting and they are about 1/4 to 1/2 inch apart except between the block it can be as much as 1inch to 1 1/2 inches. So since it is a gift to my oldest girlfriend ( about 45 years of friendship) I think I will go back and SID to be safe. It won't be the prettiest, but she is no sewer and will appreciate the thought and time. It is for cuddling in front of the TV since she lives in PA and it gets colder there. I pinned it and there didn't seem to be any problems with keeping it together. From now on I will probably spray baste and pin. I did it in sections and kept the whole quilt pinned until I stitched it.
Do you use a walking foot or a ditching foot? I just read a tutorial here and she showed a straight stitch foot (that I already have) which should work really well.