Selene on auto isn't too bad for stuff where you really need to be concentrating elsewhere and whilst I'm not sure why people think otherwise but her uptime on Fey Light/Glow is almost entirely 100%, /sic her on the boss as you are buffing and she will start the rotation before you engage giving your whm a little helping hand with stoneskins if applicable. The downside of this is that you lose the ability to macro Selene's heals to follow your own which takes a fair bit of the edge of of your single target healing ability.

Generally I use autopilot selene for T7 and T8. The tank damage isn't especially high and in both encounters it's far more important that I react to certain abilities and events immediately. Even the slightest distraction at the wrong point can cause a wipe.