Gordy, I doubt you are in any VRS at all with what you mention. I suspect the shudder you mention is probably more to do with turbulent air/tip vortices impacting the rotor system perhaps?
I am no techo head, but my understanding is you need a ROD of around 50% or more of the downwash velocity to begin the enter VRS territory. The downwash velocity varies significantly with factors such as rotor design, RPM, density altitude and disc loading at the time. It can be calculated quite accurately.
Here is a quote from Nick Lappos when I asked him the question a while ago:
"To calculate the downwash speed (which is the reference for VRS for a particular helo) just take the disk loading in pounds per square foot and multiply by 210, then take the square root. That will give you the feet per second for the 1.0 speed value.
To be conservative, if you take a descent at 50 to 75% of that descent rate, you can avoid VRS.
Here is an example: For an R-22, disk area 498 sq ft, Gross Weight 1370 lbs, disk loading is 2.75 lbs/sq ft. 2.75 x 210= 577. The square root of 577 is 24 ft/sec, which is the average downwash of an R-22 (24 ft/sec is about 14 knots, or about 1440 ft/min).
This means that the R-22 can't get VRS above about 11 knots forward speed (75% of the downwash velocity), but also that it can't get VRS in a descent less than 700 ft/min (50% of the downwash velocity)."
My experience of VRS is a lot of vibration, very sloppy and compromised cyclic response from the rotor system and an enormous and increasing rate of descent, way beyond that of autorotation. "Lose your guts" stuff.
In my opinion, recovery from "full blown VRS" as you mention will take far more than 100 feet, and may not be possible at all, as the rotor may enter a complete stall if the ROD goes off the scale.
Just a quick example: If your ROD in VRS is say 2400 fpm (auto is around 1800 or so) that is 40 feet per second. So in your recovery it takes you 2 seconds to decide to lower the nose and it takes 5 seconds for the cyclic input to take effect and the airspeed to build beyond ETL, and 3 seconds to try and do something about your huge ROD. There goes 400 feet (or more) in 10 seconds.
I think what you are talking about is more like getting to the open door of the aircraft and deciding to close it before you jump. Once you have jumped, it takes a while for the parachute to open and stop your fall.
Just my opinion!