You'll need a 5" backing plate and a 3.5". Why so many of each? Personally, I'd get 1 yellow, 2 orange, 2 white, 1 green, and 1 black. I use orange and white the most. The black one gets used, but not abused so it lasts. The 4" pads are very handy on bumpers, rockers, pillars, mirrors, etc...