He mentions the RRPM is 730 in the hover - I wonder if he has thought through its ability to autorotate, the blade area is small (hence the high Nr required to generate lift) - how is that disc area going to provide enough auto force to keep the rotors going when his engine stops?
And since he doesn't have a collective, how would he cushion the touchdown?
Definite Darwin Award territory.......
I don't think it would be achievable - if you've got enough pitch to actually fly with variable rpm only I doubt you'd get enough airflow to actually drive the blades? Kinda like trying to do an auto with the collective fixed halfway up - might get away with it if you were low, fast and flared all the way in!
However, in the chap's defence he's quite open in the comments about only aiming to get the thing to a few feet and hover taxi about. So if it's going to be horrendous, it'll be because fast spinning machinery has gone wrong!