Redo clamping and blocking. I had lots of problems getting the top skin down on the ribs without distorting the rear spar. You can not use too many clamps in this operation and you can not tighten the straps too much or you introduce twist.ZAC pic.s make this look easy, I did not think it was EASY. This evening I finally got started with the A4 drilling in the top skin. It turned out good. Finish up tomarrow.