I just skimmed the video but it’s like @Jacklr says - forearm wrist blend. He seems to have less bridge contact than Doug Aldrich but I think his motion is definitely similar. So regarding the whole anchoring question, the little bit I watched looks like he’s not anchoring. Very light contact with the bridge. Otherwise I think it would kill that rotation he’s getting.
One interesting thing I noticed is how he manages to sound pretty good even on phrases that are a no-go for his motion. Check out 14:18 in slow motion and it’s clear his sync and string changing are not spot on. At full speed, sounds “good” to me though. 3nps isn’t compatible with his USX. If he would’ve doubled up and played 6nps it would have been perfect I bet.
Contrast that with stuff that “works” around the 17:00 mark. It’s possibly 100% perfect. Even when he starts skipping strings, which he says is “hard”, then a few seconds later says he could do it all day and it’s more relaxed feeling than strumming. That’s the funny thing about string skips in a single escape context. They’re really not as hard as people would think. It takes tracking accuracy, so a little more focus is required, but there’s no “fatigue” because he’s just doing the same efficient motion the whole time.
I’ve never even heard of Tom. One of my favorite things about the forum is getting introduced to all these awesome players I’ve never heard of before. He sounds great and seems like a cool laid back guy.