Xnr,
The biggest reason why it is hard to practice the classic stuck pitch tail rotor emergencies in a Sikorsky is that there is no way to shut off the yaw to collective linkage. This means that you always will get increased tail thrust when you raise the collective pitch, even when you hold the pedals "stuck".
You actually have to sneak in right pedal as you raise the collective to wash out the coupling, if you are to try to fly as though a failure had stuck the tail rotor at a fixed setting.
The simulator at Flight Safety is pretty effective at these emergencies, and the flight manual procedures work well (I wrote them, actually!).
Have you tried the sim?
As a general statement, practicing the standard tail rotor emergencies is good coordination excercise, and good for general orientation as to the classic pitch-power-antitorque relationships, but the probabilities of having one for real are virtually non-existant.
With a stuck tail rotor pitch setting, you must find the flight speed and main torque that comes closest to satisfying the tail rotor thrust. Remember that an auto trims almost perfectly at zero tail rotor thrust, and an S-76 can fly at 50 knots sideward (lots of right thrust) with full right pedal, so there will be a mismatch in auto. The best way to correct that is to touchdown at lower rpm, which reduces the tail thrust considerably. Arrange it so that in auto just at touchdown, pull down to 90% rotor at touchdown, and the tail thrust will be almost perfect for a full right tail setting. That will happen in a typical touchdown auto, actually. Again try the simulator.