If Mr Vuichard and his acolytes are demonstrating recovery from VRS with less than 1000'/min RoD before recovery then they are nowhere near VRS in the first place.
Nick Lappos posted a chart many years ago highlighting that you have to be descending at approximately 65 % of your downwash speed to even start to get close to incipient VRS - for the full blown event it is 75 to 80%.
The trouble is that people have no idea of their downwash speed and the 500'/min figure comes from the days when disc loading was very low (due to low engine power) and so, therefore, was the downwash speed.
It can be calculated but it is surprisingly high - I know for the Sea King and similar helicopters it is in excess of 2000'/min which happens to be the same as the RoD in autorotation.
If your RoD in auto is a reasonable guide then no modern helo will get into VRS with less than 1000'/min RoD - try stopping that in 50 -75 feet.
Utter bollocks this Vuichard stuff.