Hello this thread is fantastic, i'm really glad it got this much attention, and I feel like I should respond.
Our spriest uses halo and our brewmaster uses guard and chi wave no matter how many healer specced classes we take. Doesn't really matter what your definition of 'solo-healing' is we took one healer specced player and killed the boss one and a half minutes faster than any other logged kill in the world.
Yes we used hybrid healing and tank absorbs, all 10 players contribute to the fight however they can. Of course I couldn't do all the healing without help from the other players in the raid (aside from the fact they would be playing quite sub-optimally if they weren't putting out these absorbs/healing). I think its important to note that it would also not be doable without enough dps to beat the retreat, squeezing out dps was just as important as the dps/tanks that contribute to healing.
I had intended the interesting part of this video to be about beating empress' phase 2 timer rather than 'solo healing' (by any definition) and the SOLO HEALED caps was an attention grabber. There seem to be some seriously butt-hurt egos so I'm sorry for coming across as bragging! This wasn't particularly challenging and I think a lot of guilds could manage the same thing. It was just a fun experience/gimmick I thought I would share with the community.