That would be purely up to you. I absolutely love to apply protectants with the PC since it makes it a breeze to get a nice thin, even coat on there, but at the same time, I still enjoy applying waxes by hand.
Due to the oscillating movement of the PC, you won't induce swirls. In addition to that, the finishing pad is so soft, it could be a pillow. If you choose to use the PC, you can either remove the wax from the container and lightly rub it on the pad. Another method is to use a butter knife, putty knife, etc. to remove and spread it like peanut butter. Regardless, just remember to not use too much. A little goes a long way.
You can use as slow of a speed as you want, but I like to use around 3.5 for lsp applications. Just slowly move the PC around your car with overlapping passes so you don't miss anything, and then wipe it off.
If you are still scared, just do one small area and see how it looks. If you don't like it, you can always do it by hand the rest of the way.
Good luck!
