where is the best place for the passive air intake vents? i have a romm , 5x13 split into 2 rooms , veg 5x5 and flower 5x8 , i plan on to share the output fan, bewteen the rooms, and was wondering ,about how large do the passive intake vents need to be? and should i put them in the waLLs? or use the ceiling in between the rafters? ,