Rupes machines are great and I like the pads. I have switched out from the Rupes "cut and polish products" to others with better results but like Mike said above you can't go wrong with the whole...
Using a cutting pad too fast will leave marks. Slow down to like 2 or maybe 3 and take your time. Its not a race and faster does not always mean better. you need to let the product and the pad do...
I do not have any swirls with a proper washing, drying with leaf blower and touching up with a small Microfiber Madness towel. It all in the technique not so much the towels.
You can thin any paint with Lacquer thinner. Just use a tiny bit first because you can always add more later. You can never remove it if you add too much.