I have used Collinite 845, and it works well for the winter season here. But, I would consider a different LSP when spring comes, just to try something else.
I have been using Griot's machine polishes (a holdover from non-Autopian days) with a PC. But, I intend to buy new polishes soon. I do have the DAS pads to go with the PC.
If you have a polish suggestion, either as a first step to #3 or RMG, I am happy to listen to your advice. I have very little marring on my dark gray car; however, I know I will need something stronger if I work on my girlfriend's vehicle.