You will outdps both locks as long as you are running two. Plaguebringer ticks don't stack at all, which means one or both of the are getting fucked out of their best spell.
So my group is typically:
Necro
Illy
Brig
Troub
Inq
Mystic
My first impression is that Necro gets TC and Illy gets UT unless anyone has a reason that it should be otherwise.
crap, forgot what I was thinking bout and can't delete.