i'll post what river said except in more detail
1:the rule of mamadman is ATLEAST 5 dismemberments, if you wish to add more (or your own limbs) it's just for flare.

2: you have the definition correct.

3:relax moves faster then Stiff (hold) limbs, thus making it more powerfull, so if your going to slam your arm into somebody relax the arm and use the correct joints to make it spin wherever you want it to hit

4:honestly, i have seen many people and my folder has not seen a limit; so i wouldnt worry