Not even automotive painters use a buffer anymore the oil base compounds are toxic. The modern method is to wet sand with 1200 paper and 2000 grit(yes2000grit with lots of water) this gives you great control without removing too much gellcoat. After sanding wipe on a polimer sealor and cover your boat.
Mel,
I'm confused because I am in the automotive paint business and I can assure you buffers are still used.
