Hi wilkinsi,

You are correct in that this is a design aspect.  DualVerb is the only algorithm that will allow Dual Mono processing.  If you have both inputs and outputs plugged in, the FXmix know (A/B mix) will add an option for Dual Mono.  Just turn the knob all the way right to get to it.  Please note, that this feature only works correctly in V4 of Space.  The previous V3.2 had a bug.  Hope this helps.