RG finishes can be hard to remove. I had success with a heat gun on two RG bodies, plus lots of sanding. No chemicals I used would touch it, even left overnight. There are products out there which will do it but I can't remember the names, plus they're probably a bit evil.
Try the heat gun.
Anyway, congrats on the 7 string. I just got an RG7421 for a good price and I'm doing it up. It's a great guitar, but the pickups are not. D-Activator is a consideration, only I'm wondering if it's a bit too hot. I'm looking for something to brighten mine up. Basswood isn't very interesting, so I wonder if I can find the pickup equivalent of adding a maple top.
