Some enmity questions...

[Dotsusama]

Individual enmity has no outside factors unless the boss has either no enmity table (like the Stone Vigil HM final boss, among others), or has an enmity reset.

Meaning that the enmity generated by any one player is an individual number that continues to build and only an ability like Shroud of Saints that specifically lowers their own enmity affects it. Two tanks performing the same combinations under the same circumstances (same buffs, same stance, same weapons) should generate the same enmity minus some variation in damage, no matter who is being healed more, since healing contributes to the healer's enmity and not the tank.

Also, self-heals like Blood for Blood or Inner Beast heals (for Warrior) do not generate enmity at all, IIRC. A Regen would count for the WHM, not the tank.

If you have trouble with tank swaps, what the other tank needs to do is just... stop everything. Since Provoke is just "top threat target's enmity +1" and nothing more, even a good auto-attack crit, or activating a buff can draw the threat back. It *shouldn't* if you follow with a strong finisher like Rage of Halone, but lately I have also seen enmity take a good half second or so to "kick in" and targets change, so it's best to be careful.