Going to be straight up, I have only vacuum bagged with Epoxy, never Poly. It worked best for me when doing thick I/O transoms.
Stringers would be the same exact process with a hell of a lot more tuck tape LOL... Once you have the materials all laid out, other than being messy as hell, it takes a lot of the artistic requirement out of it..
The best video I can remember is the one with the carbon fiber mast.... I think it was a "How It's Made" show or something....
GT