This will give you an edge to roll off. When buffing the tops of the front and rear fenders, open the hood and trunk up all the way and you will give yourself another edge to roll off. When buffing raised body lines or peaks, keep the buffing pad as flat as possible and buff with just the outside edge of the pad, not the whole pad, on the peak. This is necessary because if you buff with the center of the pad on the peak, all the weight of the machine is on that small area creating a lot of friction and head thereby quickly burning thorough. The type of buffing product you are using does affect the time it takes to heat up and burn through a finish.
Compounds are obviously the most aggressive.
However, if you use the above techniques the buffing material factors aren't as critical. The operating speed of your machine is very important. However, the slower speeds certainly can be used on the older conventional finishes and achieve great results. The advantage of slower speeds is obvious. The slower the operating speed the less friction and heat produced, thereby reducing the chance of burn though.