Thanks for the pages and pages of info and the specific tips for my raid, we got
our kill after ~2.5 proper nights on him.
To alleviate some of the problems we were having, I buffered the Slash groups with the hunters (adding 1 extra person to each side) and made a few slight changes to raid positioning and MT healing (using HL, HL, GH, rather than FoL, HL, GH) and a bit of blind luck. The kill was a bit shonky (I died at 1%, our druids slash group mostly died from a 4th slash, and he enraged @_@) but a kills a kill
All in all, final setup was as follows:
8 (including tanks) in each slash group.
7 healers:
MT - Paladin, Paladin, Priest
Burn - Priest, Druid
Raid - Shaman, Shaman