IMO you underestimate Human Improved Recovery in tanking situations, especially elite ToD (and to a lesser extent Epic Turigulon and Epic Cojoined Abashai Devastator, although healing SP isn't as tight there).
I'd much rather heal a human barb maintank with 95% of max possible DPS and healing amp gear than heal a dwarf/halforc one. The human can be healed by two party members spamming Heal scrolls on them every cooldown (plus a full Heal spell after Horoth's nastier spells) - allowing most healer SP to be used in emergencies.
The halforc will require three scroll healers to keep up with Horoth's damage output, or healers that drink mana pots.
The only 0 mana pot elite Horoth and Suulo run I've been in had a human barb maintank that wasn't even wearing all the non-epic DPS items - no Bloodstone/Marilith Chain/any other form of Seeker and using a Healing Amp 10/Healing Amp 20/Incite 20% DT instead of a DPS enhancing one; also no ToD sets. I've been in runs with much more geared maintanks that have required heavy mana potion use.
Edit - Half-Elf Monk Dilletante with the Half-Elf Improved Recovery is apparently better still; I'm no ½elf expert having never got further than the 'look at the face of your character' screen on one of them.