I removed the sheet metal form and trimmed the laminates about a half inch proud of the anticipated flap root final trim line. This will make the A-Rib laminates easier to do but give plenty of edge margin for the final trim.
The extension came out great! This is something I had been fretting over since I figured out it was short some time ago. All in all about three hours work. There is a lession in there somewhere. You have to keep pushing forward. The answer may not be clear in the beginning but doing nothing gets you nowhere!
Flap with extension laminates, .020 Sheet metal form to the LH side of picture,
Form with cutout for piano hinge. RH flap trimming to show how short the LH skin is