The only grain I've seen that's more open than Sapele is Wenge. If you're going for a gloss finish, you're going to spend half your life grain-filling and sanding that stuff. I'm just coming off a Mahogany body finish, which is similar, and it's unlikely I'll do one again. It's just too much work. Nothing against the wood at all, but it's definitely something you want to let a pro shop that's set up to do catalyzed finishes do. Even if they charge you $400, getting the same results yourself will have you working for about $2/hr.