Guys and gals, my arm feels like it wants to drop off when I polish and wax which is why I'm looking at learning to machine polish. I've looked at them and I'm so confused! What the difference between a das6 and das21. I don't want to spend a fortune to start with, but also if a das6 is the way to start what on earth are the difference between them!? These dodo juice, autobrite models names I've never heard of loads! Thanks in advance.