Some general thoughts on the topic of recovery from OGE Hover engine failure:
1) The Dead Man's Curve is a decent guide to how much trouble you are in. If below 250 to 300 feet AGL when the engine quits at a hover, you WILL crash. The operative issue is the stored energy in the rotor (high for a Bell, low for a Robbie), and the quickness of the pilot in getting the collective down.
2) The maneuver from low altitude is hardly an autorotation, it is more related to a controlled drop and a race to gain enough forward speed to help create a cyclic flare at the bottom. The trick is to fall while gaining forward speed by lowering the nose sharply (25 degrees, which is like pointing at the ground). Lower the lever a bunch and try to keep the rotor in the green. As the earth looms up, sharply pull the nose up to flare, and pull the collective to your armpits to use all the rotor energy left to cushion the blow.
3) If you are at 500 feet AGL or more, the forward speed you gain will be enough to get you to normal autorotation speed, so bottom of the maneuver will look like a normal autorotation, and the success is virtually assured.
4) any helicopter can establish a zero knot autorotation, with the rotor rpm stabilized in the green, and no forward speed, in a true auto state (windmill brake state). The rate of descent, however, will be horrendous, and no safe landing can be made from this condition. It is likely to be 4,000 feet per minute descent rate or higher.
OGE hover at lower altitude is a crap shoot. From anywhere near the top of the dead man's curve downward, it is very likely that an engine failure will be a real mess.