Yes the cloth will be worth the money and you can wash it out and use again and again.

Always start with the least aggressive combo first and step it up if you are not achieving the results you require. Best to do several light hits first to see what results you get.

Do you know if the paint is original? I'm guessing it is on your white 3i in your sig? The paint on my sapphire which is original is soft as butter and no way would I go at it with a heavy cut. I had to work it with a DA as I wasnt getting it to finish down very well with the rotary. The panels at the front which have been painted are rock hard and the exact opposite...