I have been running a pair of desperate mercs, sebastian, a nurse, 2 canine remains, and a bette noir.
I find that with the four models of 2ss I can stay ahead on activations and have enough models for bette noir to appear. Sebastian is great utility to keep a summon engine going. The nurse makes desperate mercs great missiles. Their ability to fire support is great as well.
I usually don't summon past turn 1 with msmourning I don't find it the best use of his of his ap. Turn 1 is for a flesh construct.