Thanks, Lonewolf - I never flew the Blackhawk but the guys at the same unit I was who did used to do reasonably quick run-ons to the runway to practice various emergencies.
Being in the skidded helicopter fraternity, we always went for little or no forward speed for an auto, and would run on to a flat surface at a not-too-excessive speed for some stuck pedal practice. However, I think with any kind of landing out in the bush on uneven or loose ground I'd want to get the speed pretty low no matter what kind of machine I was in, as long as there was sufficient cushioning power in the rotor system to get a relatively controllable touchdown at the end.
Just edited to add: the idea of a low or zero-speed auto for a non-functional tail rotor works for me - it's always a discussion point no matter what you fly, but I tend to agree with the point that it's going to be the forward speed and possible rollover that will get you; a reasonably controlled vertical impact even with a bit of turn seems preferable going into unprepared ground.