Maybe put the bowl on a flat sanding surface like we would a water neck.
Though the moto tool would obviously work, it would be hard to get a uniform surface with it.
I cannot do that. Man that would make it easy. The gasket area on the float bowls is recessed. In the middle of that recess is the casting ridge I'm talking about. When I get the gaskets and emulsion jets, I'll get some good pictures and post them.