Which tool do you have? I've never done it but, if I did, I would prolly scribe an identical reference line on each pad to keep the cuts equal.
I was actually only going to do the very edge of the pad so the disc slips in there easier. I use a quick change axle setup. Either way, it looks simple enough....
I've done it using a mill or a steady hand on a bench grinder. Only tip would be to consider wearing a respirator.
Using a 3' screwdriver to remove a dust seal on a wheel that's laying on its rotor is two reasons in one application. It looks like he put his whole weight on it. Third reason? Does anyone really need a third reason after that demonstration? Here's one - get a bench and get off the floor. If you're doing enough seal removals, wouldn't you buy a seal remover? They're $10. Besides, if you're looking to remove rolling resistance for drag racing, just yank one of the calipers - easy 50% decrease in front brake drag. Is the guy as smart as he thinks he is, or...?
Well, since I have a spoon, I'll stir. He did say "how you might do it at home" and removing weight from the front isn't desirable in any way. I think he dumbs it down for the masses. He did make a "streetable" Bandit the first to go under 8 seconds, so he does know a few things.
Yeah, he is a extremely intelligent guy. He realizes most of the people watching his stuff are idiots and dumbed it down to yalls level.