I assume you're fairly experienced multiboxing if you plan on running 16. But even experienced I really doubt you'll be able to micromanage that many at once so stuck with option 1 in Wubsie's post. I have a pretty good priority rotation that is a bit low on DPS but survivability is top notch.

You don't need that many for mythics or LFR are you mostly after WPvP? DKs seem a good choice for that but 16 a bit overkill it would be fun with 5.