I bought one of the Meguiars orbital polishers after trying one out at the TM workshop morning over at their Daventry HQ. I had a certain bonnet in mind, but I'm minded not to as yet.
Amongst the things we asked on the day was how much, how far etc etc and the consensus was not to go too far into small gaps unless absolutely necessary, but to use finger pressure to do the same role, until you achieve a uniform finish to match.
It appears most dual action orbital polishers are much of a muchness, with certain ones having better switches, feel, quality and the like, but they all depend upon the operator, and I was really surprised just how little practice they need. Neil had come along in his wife's car, and it was the bonnet of this we were practicing on..!
As to compound, we used their polishing compound (not sure exactly which, but will look it up..) on an up/down pattern with light pressure.
I think Stewart is the accomplished DIY expert with this, he was taking many notes..!!
Does this help..?