I would like to offer some advice, RE: the Five-Headed Dragon that doesn't normally come up because tanks don't typically notice it.

It's ideal to tank him far back, yes. However, don't move him back at the start of the pull. When you pull, either melee pop their CDs and you move him disrupting their GCDs and causing a DPS loss, or they don't pop their CDs immediately which also becomes a DPS loss. Just wait about 15-20s before you actually move the boss back - this also allows you to actually establish threat as opposed to wasting TP on Tomahawks or whatever.

Also don't follow that OT guide you linked, nobody does that stupid thing where you stand in front of the Ahriman and take excess damage for no reason except this specific person. Ideally just be aware of if the MT dies or not and 'voke ASAP with OP or a combo'd move (any will do, typically, but ideally Skull Sunder or Butcher's Block) in Defiance.

Your main concern as MT is keeping the boss still. Your main concern as OT is picking up adds that spawn and dealing with the mechanics everyone else has to deal with.

GL in WoD.