Really interesting group, with two bards and two enchanters. I have never seen that setup before, but it does make some sense. By having a paladin tank, you can get by a bit easier with a single healer. It sounds like your characters are very well-geared, with raid drops, mythics, etc. Those things will likely always be beyond my reach, as I'm in a guild by myself. Does most of your dps come from your bards or from your enchanters? I suppose with the overlapping buffs it would be a bit like having 4 dps classes, whereas most groups end up with one dps or two dps classes.

The fact that you mention TSO encounters tells me you're able to survive those with a single healer. That's very interesting. I've had it in my head that double healers at that level are an absolute necessity for 6-boxing, just because the margin for error with a single healer is so thin. With the right AAs, I suppose you can help offset some of that. I may try a single healer group sometime, just to see how it works. I'd probably go with either a warden or a templar, as my very limited perspective suggests those are the two most powerful pure healing classes.

You certainly don't have to worry about mana with that group. I run a troubadour/illusionist in my group, and that pairing with expert or master regen spells means I basically can't run out of power. I suspect that later encounters may involve strong power drains, and at that point dual mana regen may be a luxury I can't do without. Today, with the content I'm doing, it's overkill. My power never dips below maximum even on epic fights.

Good stuff. I enjoy reading about other people's groups and what works for them.