I'm running it with 7 players, at start, 3 dead yet, 1 going away, I will go on with 6 character (and 6 players), maybe 7.
The SC is hard and you better be at least 4, the best is to bring with you npc or have 2 character each, to halve the damage.
3 gestalt is only 3 targets for the baddies.