Thanks for the quick response - that was a big help.
Hopefully when I have something respectable I'll create my own thread. If nothing else, this has been one hell of a learning experience.
Edit: One more quick question, for whoever is good with GIMP - when I turn off the layer masks under the channels, does that turn them off in whatever layers I've attached them two, or did the program make a copy of them for that purpose?
Thanks again, everyone.