Hi to the Community...

I have to be honest and say first that i am a newbie so beware me with my questions. I received this toy today and will like to be clear before i start to use it on my 3 cars (Nissan 350z 2004, Ford Explorer 2011 and Mustang GT 2019). To me, my paints are good as i always have maintained them manually.

Now where i want to be clear is with the Backing Plates and Pads combinations to start.

1. The Backing Plate that comes with the Polisher is 6". Can i use 6.5 and 6.0 or 5.5 with this backing plate?
2. Can i use a 5" Backing Plate to use smaller Pads or vice-versa?
3. What are your favorite combination and pads brand?

What will you recommend me for better combination?

Thanks in advance...