Just because your not an expert doesn't mean you can't use the colors. Each color does somethign different and it's really not that hard to switch and know which ones to use.

From more to less cut is Yellow, Orange, White, Black Blue

Like Rohn said, I would not get yellow and get the others.

I would get more orange than anything, white and black the mid range and blue the least.

Yes, you have to get a smaller backing plate as the plate would extend .5' off your pad and it would hit the paint.