If you read Mike's articles, which he's no doubt linked to, you'll see him recommend a 5" LC Urethane Backing Plate, and the standard "go-to" 5.5" LC Flat Foam Pads.
I took his advice, and these do work very well for basic Polishing needs.
The 5.5" Flat Pad seems an ideal size, to correct fairly quickly, covering the larger panels, and are a good compatible choice for machines like the PC, Griots, Megs, Harbor Freight DAs.
I have found these Pads to be quite durable, and IMO are a very good value for their cost.
Have a good number of the various pads in this line-up and you'll be good to go.