actually i have a questsion as well abt ufo i have a spinner but is it better to use it on top of a fresh resurface or on top of a already finished surface or what underlying grits have worked well
In my opinion,
Given the nature of UFO (It reduces overall hook and it reduces the backend, while increasing length), I must assume you're using it on your weakest resin ball to enable you to bowl on very lightly oiled, very dry lanes. So, based on those premises, you should sand this weakest of all your balls, to 4000 grit and then apply UFO.
If you're not facing the driest of conditions, I can only assume you using a normal polish like Snake Oil, to get more length.