just being a little nitpicky, but disagree with a couple things. for one, solo healing this is about more than just focusing heals on the tank. whm should be able to single target regen on melee +tank and use prism to aoe stoneskin on melee + tank. with constant regen on melee (and popping featherfoot on cooldown to help out), the actual need to directly cure them is pretty low outside of the occasional curaga, and cure bombing the tank isn't really necessary, either, as long as tank has regen and is curing themselves as well. i guess you could try setting it up to allow your whm to just focus on the tank, and i'm sure that works, but i don't see how that's much of an attestation to the whm's skill. imo you get more out of the whm position by allowing them to multitask.
as far as surviving the first megaflare, i think maybe you're misappropriating what's going on. he always jumps up and megaflares immediately upon taking ~2500 damage. if you don't do 2500+ damage, he just sits there and spawns meteors forever and ever and ever. as soon as you cross the 2500+ damage threshold, he jumps and megaflares. now, it's possible i'm wrong about this, but i'm pretty sure unless you're somehow tracking damage so carefully that you have every DPS use some huge damaging ability at the same time just as he's on the cusp for taking 2500 damage, there's really next to no way you can do so much more damage before he actually registers it and jumps that it would somehow dramatically impact megaflare damage. however if you had a thm casting aoe sanguine rite, that should just about cover it.
the *only* other possible explanation i can think of is that the megaflare damage is tied to how long it takes you to actually do 2500 damage to him, but i don't really think that's it, either.
we'll be running it again tonight and we'll test this out, and maybe i'm wrong... but i'm preeeeetty sure it's not the case. (if i am wrong i'll happily return to this thread and admit as much)
and completely aside from that- even with just 2 melee dps and 2 thm/blm it's still easily possible to finish the fight in 23 minutes or less without STR/INT pots. while being able to use pots would help speed things up, it really shouldn't be *necessary* as long as people aren't getting hit by dynamo. the self heal he gets from dynamo is generally the main reason people time out.