GRP arches and nose?

[Talonmotorsport]

Just a quick question to any body who has made their own nose cones and wheel arches in GRP. How much of a pain is it to make the plugs and moulds? I like to think that I have a fair eye for equal and even, I did industrial model making at collage so have a fair idea of how to go about it. Is it worth the the out lay for the materials, bearing in mind that I could sell a more complete kit if I had decent enough moulds?