I stick to the 6.5 pads. I do however have a 3 inch backing plate with Cyclo pads that I will put on to get tight spots or I will use it on the rotary at about 2000 RPMs with Plastix to get out haze on talk and head lights.
With the PC, I can often reach best with the overhanging edge of a large pad. Sometimes it fits into spaces the 4" pads can go (because of the size of the PC's housing). Gotta be careful doing this with the rotary though...
