The burr style is a prity standard practice when working on surfboards. From experience I have had in the past normal fluted bits can tend to heat up after a long duration and coolant is not a option and on eps this can end up melting the foam which can make a right mess. The burrs also give a great surface Finnish.

im open to ideas ?

I played with the two burrs I have today and even the fine one seams good.

No idea how hard or I fit would be posable but would it be posable to make a blank bit on a lathe and then coat it in some sort of abrasive grit? I'm assuming balancing would be the major problem?