When I used to make knives I never bothered using a finish on those heavy oily woods. I would take them down to about 1200 grit on the sander and then take the soft buffing wheel to them. After buffing cocobolo, as well as other oily woods, it had that deep gloss finish that looked like had been sprayed on.
My brother carries a knife I made about 10 years ago for him with a cocobolo handle. I encourage him to beat the heck out of it so I can see first hand how my knives hold up. The finish on the handle is very near as glossy and beautiful as the day I gave it to him, the cocobolo looks better than the brass finger guard. If he ever wants it looking new again it'll be a 10 minute fix on the buffer.
I'm not sure this is a feasible option with multiple woods in the riser but thought I'd throw it out to give you some ideas.