Funny. I thought they used a similar one to us, and I'd never heard of that happening. Not that it couldn't, just that I hadn't heard of it. And we certainly don't do the asymmetric thing very often.About 110-120 iirc. With enough wind, it would be around 100. We also had to worry about breaking tow links with the hummer, so you had to be careful.
One thing I do notice, being in an aircraft that uses the old-style holdback, is a distinct pause in the cat stroke. Maybe "pause" is the wrong word, but I feel like I can definitely feel the split-second between the holdback metal stretching and finally failing.