Nice job. I hate snakes, so I don't do snake skin, but I like the looks of dyed rawhide. I'm going to try my hand at painting one as well. Whatever you choose, it'll be great.
I've use tru-oil a lot in the past for everything from firearms, to knives and bows, and it works really well, but I bought a can of marine varnish and really like it. I think it will provide a bit better moisture control.
Nice job on the bow and food luck in the woods