Leaning post storage help?

[PeterM]

I finally pulled the trigger on a 21,though not a classic, so I hope I can still post here. (thanks guys for the advice leading up to my buy)


I plan on unbolting leaning post bolster from framework and putting SS piano hinge on it so it tips forward. I want to build and install a box for storage under the bolster. I am a pretty competent wood worker but I think this will work better and be lighter as a fiberglass box.

I never worked with fiberglass though, but this seems like a manageable project to get my feet wet. So how would someone start this? Make a form out of wood and lay fiberglass over it? Cut edges with saber saw or dremel? Sand and finish with gel coat or awl grip? See I don't know anything. Any advice appreciated. Thanks!