I removed the peel ply, trimmed the new edge down to about 1/8" wider than before, then sanded both sides of the lower edge smooth ready for 2K primer to seal the surface. When that was done, I checked the fit in the end of the port wing. I then scuffed the upper edge at the ends around the new layup, glassed in a wide strip for increased grip area, layed up the right angle flange and applied more peel ply. Once again I used the beam to keep the tank wall flat.
Would I make tip tanks again given all this extra work? ... hell yeah, but I have to say there's nothing quick about the process! Tomorrow I'll order a couple of ProSeal semkits for the inside seams, internal water drain threaded receptacles and the inspection flanges. I also need to start thinking about best placement for the fuel line finger screen, plus the vent entry point and associated support fixtures.