Well never tried that,but with the glass you can use cardboard as a mould/guide.Don't mix it hot or the whole thing will go wrong.I think your weight will go up alot.You can get some COOL colors now,try Dennis Kirt,water craft parts book.Feel free to holler back if you need info on the glass.
A friend of mine up here is making a few stocks now. He does taxidermy and it wasn't much of a stretch to make the molds for the stocks. I could probably get you in touch with him if you're interested.
