I sometimes think we can be too critical of ourselves. Maybe here is another way to look at this 1/4 seam that is driving you crazy!!! If you make your quilt with all the same seam, whether its a perfect 1/4th or not it will all work out because the seams are all the same. When you finish are you pleased with your quilts? I mean after all do you have quilt police that come and check the 1/4 seam? To be honest, after the quilt is finished no one knows if the seam was perfect or not. I look at it this way, my quilt may not be perfect but it was made with love, and those that receive them will hopefully love them for the same reason. I honestly bet they never even know the seams might be off a tad. Just have fun with your quilting, enjoy it, and stop worrying about being "perfect". One of these days I bet it will happen all on its own : )