Force Trim function  

Almost impossible on finding consistent resources on the Force Trim function as it seems every helicopter is a bit different as I get different answers in the forums or on the web. I would like to know on how it works from a piloting perspective in the Mi-8, Mi-24, or KA-50  models. I would appreciate if a real life pilot would find the time answering some of my below questions related to the force trim function.

Are the following statements correct:

(a) If I engage the Force Trim function the cyclic locks into that position and this is the new 0,0 position.

(b) I can still make corrections but the range is now limited and if I exceed that limit, Force Trim will disengage.

(c) If I move the cyclic from that new 0,0 position I will feel a "spring" load, returning the cyclic back to the locked position if I would let go of it.

If the range (b) is limited, by how much?