Tested attached SHAPE-ARMA mission (Takistan, AIA TP). Mission specs:
Mods used: http://play.withsix.com/arma-3/collections/h6c92ulrtkqMMdixqzMaiA/shape-campaign-2014-v4-4
Mods info: http://shape-arma.com/shape/campaign-requirements/
Map: Takistan (via AllinArma Terrain Pack)
Slots: 14
Type: Coop
AI's: 80-105, dynamically spawned
Helicopters: yes, opfor, AI controlled
Tested with 2 clients
Server FPS with Arma3 1.32: 47-50
Server FPS with Arma3 1.34: 20-33
{F25081} {F25082} {F25083}