J.,
If you decide to try wet, a professional bottom refinisher (of boats, that is) told me he uses emery paper for course wet sanding. Wet and dry paper is generally only available down to 230 grit. Wet sanding will keep the surface cool and flush the debris away. If you're using an electric sander it must be double grounded and connected to a circuit with a ground fault interrupter. An air powered sander is preferred for these reasons. You can keep your work area wet by holding a wet car wash sponge "uphill" from your sander and applying just enough pressure to keep a trickle flowing. Good luck.
Geo. C.