Definitely more than one way to skin a cat but if you're worried about the butt moving after a 12 inch long .020 deep cut, I think you may have bigger problems with your handle wood than you know. Maybe I'm wrong but if your handle is moving after cutting a little groove in it, it's already full of tension and is a bomb waiting to go off whether you groove it or not. Not a good idea to grind it all out in one pass but I've never had much problem shaving it down in 4 consecutive passes. Finish the cue and square the corners right before installing the wrap.
Sorry, Dave, I just don't see the reason to take .005 4 times.
If you're so worried the wood would move if you took more than .005 off in one pass...
I don't see why taking down .030 and doing a .010 or less ( + 220 grit sanding ) final pass could be wrong, but I am all ears.