Need advice on buffing

[1999 Tahoe 4x4]

I just bought a Dewalt DW849 Buffer. Tried to use it last weekend but I'm not happy with my results. Although it did a great polish job, but I wanted to get some fine scratches and swirl marks out too, and this part of the job did not really happen. Of course guess I know why: To start and to be sure, I have only used polish and polishing wheels.

 

My question is what is a good combination of polishing material and wheel for my purpose (fine scratches and swirl marks). The most I'm afraid of is to cut too much paint e.g. at edges. So I don't mind using something less abrasive and going over the truck many times.

 

In case color matters my truck is black.