For what it's worth, Practical Sailor also has an article on painting this month. It's well worth reading.
BTW, trying to put on any dark color rolling and tipping doesn't work very well. I'm not sure why, but the color doesn't seem to come out evenly, and the dark paints, with more pigment (I guess) are more prone to sagging on vertical surfaces.
If you are indeed working with gelcoat, then I agree with Sway. Wet sand it with 600, then 800 grit wet or dry paper. WET SAND IT! Use a bucket of soapy water for your sandpaper. It'll help the keep the paper from loading up, and it will remove all of the old waxes, polished, road oil, etc. Then get after it using a good buffer at no more than 1800 RPM, with a good bonnet.
Try and work in the shade if you can to keep the temperature down. If it's as oxidized out as you describe, I'd start off with 3M Super Duty rubbing compound, then after getting a start on the shine, I'd switch to 3M Imperial to bring it up the rest of the way. If you want to be fanatical, you can do it with 3M Finesse It. Then put on at least two good coats of wax. 3M or Collinite. I personally have had rotten luck with McGuire and Mother's waxes.
Don't even bother with the combination polish/waxes. Like most compromise products, they don't do either very well.
BTW, I've done what you're doing, but on a 56 foot boat. It took me three days to sand the really bad areas, compound and wax the hull. (long days...