The statement above referring to knowing how to angle the pad to direct splatter, that is very well said! That alone should save quite a bit of clean up, it comes from experience.
As for using the GP, I use the highest dilluted mix that I can, just enough to really have a foaming action when agitated, I use a horse hair brush actually (looks like a toothbrush), but isn't. I do this as I wash the vehicle for the last time, after soaking the car down, I usually leave enough of the product on from polishing so that if I contact the paint, it never touches the paint due to the film. I clean all the hard to get areas, around badges, trim, etc, then I wash down the whole car. I have seen to many nice buff jobs ruined because the wrong brush was used, but in most cases if done right there is vertually no chance of harming the paint unless you get carried away with scrubbing.
Also, one thing I have learned, if you are going to dress the plastic on the motor, this is the time to do it, before the final wash, it saves from time lost to trying to wipe away greasy overspray. Also, clean all the jambs before the wash, for reasons I cannot figure when certain compounds get wet, then dry, they almost have cement like quality. Try to remove before the last wash.
Another tip that helps a bit, try to dress obvious rubber trim before any buffing, the silicone allows you wipe of any dust or built up areas.
Good luck and have fun!:bigups
