Check out building with magnets at Paul Johnson's (cafeenman) at:

www.airfieldmodels.com

Be careful, you can spend as much time going through his website as you do on the build itself!

The method Dave Platt uses is to build on top of glass, gluing the assembly directly to the glass and then popping it off at the end with a razor. If you are going to tackle a project this big, I really suggest his videos. They're pricey, but worth it. For your build I would recommend his building and fiberglassing series and his advanced building techniques.

Scott