You should clarify tail rotor failure. There are a myriad of failure modes, control (lack of or jammed), drive, blade failure, t/r departing the aircraft on it's own or with the gearbox as well.
I think you might find the EP's in the R22 manual are conjecture to satisfy a requirement. The Bell 205 manual (who knows where you will find one) does have extensive info after the many failures experienced in the SEA conflict.
The loss of the TR with the Gearbag is probably not survivable in AC without a decent offset in the MRH. Find the numbers and do the math on an R22 or B206. Probably lawn dart central.
If you think about it long enough you should come up with some answers and here should be the place to get them verified. Training will give you some idea but not the definitive answer. The result would possibly be better than no training at all, with luck.
With reference to the quoted Enstrom failures on another thread, the TR is that bad on this aircraft you probably wouldn't miss it. As for the Robinson's - Frank IS Mr Tail Rotor, shame he used one for a main rotor on his aircraft.