Hi Greg , Debra
I use Farecla 1000 grit and 1500 Grit. I also use a flat pad from an auto shop about $20. Screws straight on m14 thread on a makita polish/ sander. There are different hardness in the foam pads. Black which is soft. I use the orange pad. With a similar technique to above.
Sometimes the gelcoat is so porous / rough that i wet and dry the hulls in 800 grit first then 1000, 1200,1500. I then start buffing.
Tash's mossie had bad gelcoat and hours of TLC came up like a treat.
I don't use polishers as it has wax in it. Wax slows you down.
Hope this helps