RE: KMP Stuka-build details
This is exactly the situation I was warning about some time ago with the center cracking. Your assessment of the build up of the manufacturers center section is quite accurate.
Hopefully you have fixed the manufacturers defect and it won't end up like the one described by me some time ago.
May I further take this opportunity to recommend other owners consider my original recommendation of glassing the center wing section. I am no expert but I know a duck when I see one.
All the best
Mark