pappabear, the body is made from: Two layers of vinylester tooling gelcoat.
Two layers of 225 gram chop-strand mat glass.
The reason for vinylester over polester is the minimal shrinkage with VE resins.
The reason for vinylester over epoxy is the issue of bond between gelcoat and mat layers and post cure issues etc.
The C-cab would be one of the easiest to do if you used a big T cowl and the rest flat sheet with minimal bending.
If you want a T model C-cab....
Like Bills bigger projects, most compound curves can be accomplished with profiles and filling the gaps.
This another shape done with profiles and bondo. The grille shell is formed aluminum.
The key to getting the desired shape quickly is to use wipers that approximate the final curves. I use 1/8" rubber sheet cut into
small shapes or squares to do the final applications of putty. They form to the underlying shapes so you don't have to spend hours sanding
off mounds of putty.