GPU Particles on multiple heads?

I haven t got the machine to test right now, so my question is: given a 4 projectors, on 2x TripleHead2Go (dual head) system on ATI 6970 will a GPU particle system work?
Which kind of start parameter should I issue? (/dda 1 /dda 2)

Today I could test the machine, it simply works as it is, sometimes it needs to be banged here and there (!) to get it working but there is no need to use any start argument, is this new in 28.1 ?