If I were going to use the orbital machine you received as a gift for wax application, I would use a terry cloth bonnet for application. You can use any liquid wax, off-the-shelf or special order. It doesn't appear that you expect much in the way of defect correction out of it, so I'd say use the polisher. I used one similar to that for a few years before I was able to step up and get something like a PC. You gotta use what you got, and since you have that go ahead and use it.
Contrary to popular detailing forum belief, not everyone can start out fresh using PC,
Flex,
Pinnacle or Zaino stuff. You can achieve excellent results using stuff OTC. Not saying it's the best stuff out there, but use what you already have until you can step up and get something else.