I like the FAT wrench...it's an easy-to-use torque wrench in a firearms-appropriate range, and is useful for lots of things besides scope mounting. The level-level gizmo is a total waste of time. It gets your turrets level, not your crosshairs, and the two are not always the same!
Lapping the rings is a good idea, super easy to do. If you mount more than a couple of scopes, try putting on your lower rings and then dropping the scope tube into them. They are often so poorly aligned that you can see the uneven gaps with your naked eye, or the scope tube won't even drop right down to the bottom in a lot of cases. Instead of just jamming the top rings on and tightening them up, thereby twisting the crap out of your precision optical device, lapping the rings will remove the uneven stresses and protect your scope. It also improves the grip the rings have on the scope, minimizing the chances of the scope moving in the rings on a rifle with heavy recoil. Plus, it keeps your scope tube from getting marked up by the rings.
You're not just screwing a handle onto a barn door. Do it right.