You should be able to get away with a SS and a Regen and DPS. Like Rollan said I am in Cleric Stance far more then I heal. A WHM can put out about 150,000-175,000 damage easily in AK. I holy bomb groups of three or more, use Shroud when I need to back off and heal. If I am not at full MP I Aero stone the target mob along with rest of DPS trash and bosses. An AK run requires about 800,000 damage to complete so 20%ish of that is huge. If you looked at it from pure damage per second that's roughly 7 minutes of damage that would have to be made up by the other DPS. Come to think of it this applies to almost all content for me besides coil and phase 3+ of Titan. The thing you have to get out of your head is having the tank at 100% health all the time. I let them go all the way down until a Beny is required even and I keep Stone 2 things to death.