With regard to using your Makita rotary with smaller pads, that's exactly what I did and I have no problems with it. Yes, there is an argument to be made for a smaller form machine for tight spaces and less weight...especially if you're doing a lot of it but I don't. I do maybe spot corrections here and there and headlight restorations.
I outfitted my Hitachi rotary with 2" and 3" backing plates (actually slightly smaller) and 2" and 3" pads. I found the Flex rotary outfits work on my machine just fine. I also have 2 - 1" extensions I use in those hard to reach spots.