use green board to bakc up the humidor room I know a wholesale cedar source out fo the DR for you and contact CMT to get the best humidification system, remmber not to put a return in the closet if you plan on using HVAC and seems ther emight be a confusion about spansih cedar, it is nto really a cedar that is just what they call it, it is a hardwood with a cedar smell, as far as your smoking room I beleive that Hoenywell makes this contraption you can actually put in your vent system with etra return, also a company called EcoQuest makes a electrostatic system for the vent system tha should kill the stale smoek smell and whatnot PM me is you want the contact for the cedar, it is not expensive to ship as they ship by containers and fill several orders at once so they alwasy ship a full container then havce it distributed once it comes stateside