As for polishing I can't recommend a polisher but something I can recommend is to be VERY careful around edges and sharp bends on the panels. Those areas (especially sharp bends) will have less coverage and will wear down very quickly.
Trick is to use the polisher in such a way so that the rotation of the pad is spinning away from the edge. This will minimize the amount of pad/compound that contacts the edge.
Another thing is to be sure the nap of the pad doesn't become slick with compound, otherwise it will tend to heat up and literally melt and smear the paint. Back in the day we flipped the polisher over so the pad was facing the operator, turned it on and used a flat bladed screwdriver to raise the nap.
Not sure what compounds you are using but if they don't come in a squeeze bottle you can use one of those squeeze bottles available for dispensing catsup and mustard. You can also dilute the polishing compound with water if you think it's cutting too easily.
