Actually, if this is your first rotary buffer, I would recommend getting a set of "tools" over time for it such as 3.5" backing plate for using 4" spot repair pads, even a 2 3/4" backing plate for 3" pads, a 5.5" backing plate for 6" and 6"5 pads, etc.
The rotary buffer is a very useful tool for specific types of jobs but you need the right backing plate sizes and pads to take advantage of the tool.
I love these backing plates because of their thick foam interface,
Meguiars Solo Easy Buff W66 Rotary Backing Plate 6 Inch
Heavy Duty 5 Inch Rotary Backing Plate
And you can drive a variety of sizes of pads with them...
Ron aka rsurfer is right about the power/speed topic, when working on clear coats you don't want to generate heat and most procedures can be tackled around the 1500 RPM range. I rarely go over 1500 RPM and if I do it's probably on some old and neglected lacquer finish.