Oh, I feel your pain! I can't do any type of mystery block/quilt project. I can't stand not knowing what the finished project is supposed to look like. I too can only do a "planned" scrappy project. A suggestion for the diagonals with the 1/4" turned under: I would use a piece of freezer paper, ironed to the wrong side of the fabric. I would make sure that I cut the piece short the 1/4" and then turn it under and press it making sure I starched it well. Good Luck!!!