the Warwick wax is a mix of mineral oil and beeswax, it's really designed for use on oil finished woods so the mineral oil can penetrate the wood. I don't think it'll hurt anything, but it'll be really greasy and won't soak in, and will be more of a pain to polish off. not to mention you might get grease stains on your clothes of you don't wipe it all off completely.
Yep, my Rebop is oil finish, that's why I use it. I buff it in with a soft cloth and there is no residue. The bass feels dry to the touch. I live in a very dry climate so I figure keeping up on it is a good idea. I have a wax oil mix for my butchers block and its definitely a lot oilier. The Warwick wax is much more towards the wax end of things.
I've never bothered doing anything to poly or nitro finished basses. Maybe wipe them down occasionally.
