I can't help with the belts. The problem is, that some belts are survived and are parts of museum collections, but we do know the used aircraft types. And there are not many cockpit pictures.
So you have some artistic freedom.
For the paint problem:
I had the same experience on the older brass PE, but not likely on the new thin STEEL series. The paint sticks much better on them but you should avoid a hard bend. With curved shapes (as the real strong belts) the paint should stick.
Just my thoughts.
Cheers,
Frank