James does explain how there. Like most things it would only take a couple of minutes actually doing it to 'get' how it's done. There's probably also youtube clips giving an even better idea about the movement required. So knowing the effort involved, if you had another car to try first, I'd think the wheel is far less effort. (Heck, I'd even think it worth buying a smashed door from a wrecker for $20 to test on first - or just explain to the wrecker and ask if you can do it there for a few minutes with a cordless drill.)
Admittedly I'm biased because I absolutely hate rubbing adhesive off for hours. The above link I posted was probably the cheapest one. But once you get the rhythm right with a wheel it would come right off. Especially if you paid a bit more for a better one.
e.g. Never heard of this particular one before. It's just the first one I stumbled on, on youtube. Twice as much at $35 but looks like 3 or 4 times the surface area, and has spaces to 'fan' the metal with air as it goes would prevent the surface temp climbing too fast. Just saw it has a money-back guarantee where they even pay the return shipping. I'd jump at trying that first.
at:
http://decalstickerremover.com
Ok, he's stripping off letters that are freshers and so would come off sooner than a 240 decal. But take note how fast it happens. So you'd do one area for a few seconds, moving the drill the entire time, then skip to a new area leaving some cool metal in between to lower the temp of where you just were. That way the metal would get less hot than when you park the car in the sun. Then return to that spot later, etc. til it's all gone.
Btw... It's not DECK-ALL. It's a DEE-CAL, lol.