What grit sandpaper for rev solo II?
 

So i finally got myself a rev solo II pickup and as expected, its too large to fit in my bass. So i read the instructions and it said to sand it, but i'm wondering, does it matter what grit sandpaper to use? i'm thinking maybe fine or very fine grit, but im a little unsure about it.

I don't think it matters, except as a question of time. Just don't sand the side with the logo.

My bridge had very a narrow space so I modified my bridge instead to fit my RII. I also use a paper shim to ensure the PU is held in w/proper tension.

The RS is made out of spruce right? Can't go wrong with a piece of 120 and 220. If you want to be extra careful then start with the latter then switch to 120 I you want to speed things up.

Make sure that you use a sanding block or functional equivalent so that you get a nice flat surface.

I never modify the pickup, I always modify the bridge. YMMV

Another reason to choose this route is you can resell the PU if it is unmodified