0: Compose hair before translucent objects. 1: Compose hair after translucent objects, but before separate translucent objects. 2: Compose hair after all/seperate translucent objects, 3: Compose hair after translucent objects but before translucent render after DOF (which allows depth testing against hair depth)
Usage
r.HairStrands.ComposeAfterTranslucency [value]
Set via the console (~) or in DefaultEngine.ini / DefaultGame.ini.