Did I hear my name? ^_^
That belt grip sweep is my new baby. Well, it's my last baby, my current baby is overhook X-Guard footlocks. But it's an awesome sweep that works very well and in moments when I can't get the normal kimura from half, this sweep is really really strong. Only disclaimer is it IS possible to base against it if you expect it, but there's no chance of actually passing from there, so all you're doing is stalling. (Basing against it involves sitting back on your heels and then basing on your hand at a diagonal so there's no way your base can be brought forward even a tiny bit.)
I think the main reason it works so well for him is because he's tall enough and long enough to get over the back and get a nice kimura/belt control even if the person has good posture. If your arms and body are shorter, it's a lot harder.
In terms of the sweep, the mechanics are really fairly simple. Get the kimura grip and the belt grip, whilst keeping their wrist pressed tightly into their hip (for control, and it will also help a little with the lift later). Then a big turn into them for the load up then pull their weight forward onto you. Once you feel the weight, punch the hand up into them to lift them then roll over your shoulder on the same side as their head, and land neatly in top half. Awesome sweep, and been working for me very well in the last couple of months. Even taught it a few times, with some success. Key thing is that you are turning a corner and bringing them over yourself, not headfirst into the floor, they will always base against it. If you take them over yourself, they have no base because the hand on that side is underneath them.
Sorry for poor explanation, but honestly most of what you need to know to do it can be gained from watching the video of him doing it and just drilling it. And most importantly, believing in it. Works really nicely!
Anything more specific people want to ask about his game? To be honest, my time spent on top of him in half-guard is fairly minimal. I spend a lot of time under mount, for some reason I can't quite put my finger on. @_@
Take care,
Oli