Use that changer but tape up the clamps so they do not scratch the rims. Order a NoMarr bar and balancer and you are good to go. Mount the tire changer to a solid surface or it is a hassle to use.
I mounted mine to two 2x6's. crossed under them so I can stand on them while using the tire machine but then store it later. It can be a hassle sometimes but works well.
Yea i ended up getting that ebay (same as old harbor freight one) tire changer, one of those ebay balancers, the no-mar bar, and a no-mar 'yellow thing' (thats the actual name). I mounted the tire changer to a pallet so it's pretty stable.
The tire changer worked well but there are 3 things I noticed. First, like you said, you have to put something on the clamps or your rim will get scratched. I used t-shirts cause I didn't have anything else at the time; the shirts ripped a little and ended up scratching the rim a bit. I'll use tape or something else next time.
Second, you have to clamp down the wheel really hard or it will rotate and make the job impossible.
Third, the tire changer sits up kinda high so when you're using your body leverage to put the tire on, the bar is sitting above your stomach or on your chest almost (instead of your waist/stomach). Makes using leverage a little harder, but not impossible.
Overall, changing the tires were really hard for me...but I think if you use good technique it's not that hard at all. My second tire change was a lot easier than the first.