golfugh: "Set them full range, no crossover for the mains, crossover the rest as required."
Indeed. Unless you define your system as not having a SW, the pre-pro sends whatever is on the '.1' channel to the SW. Defining any of the 5 speakers as Small sends that speaker's bass, too, to the SW. I define my system as not having a SW and then drive my pair of SuperSubs in parallel with the front-L/R channels. That way the 'Subs work with 2-channel signals, too.