You're ahead of me. I quilted an entire baby quilt on a long arm and it looks terrible. I have to take the whole thing out and I haven't even started. I will have to look up the videos on how to skin a quilt for help.
Speaking of mistakes, I once spray basted an entire quilt together AND got it up to my sewing room to start quilting before realizing that I had put the backing on wrong side out. Tear that one apart, wash the backing and start again.
I go by the 50/50 rule. If there is a 50% chance of getting it wrong, I'll choose the wrong 50%.
Watson