Oh, I didn't think texturing would count into the memory limit...
You are very persistent to work so close to the memory limit. I would stop before seeing how hard PicoCAD is chugging along.
I guess you can win a bit by having a simple plane for both attaches under the wings (using texture alpha to split them).
Also I'm under the impression that extruding is less expensive than adding new meshes, but maybe we could get a word from god about it.
Anyway, love your seeing your elaborate models, keep it up!