We are finishing a 11' x 20' x 80" room in the front end of our basement. Our HVAC company installed two 6" heating ducts at the top of the wall between the room and the unfinshed section of the basement (other three walls are exterior walls), but did not install a return vent. From what I have read there should also be a return vent about 12" above the floor. My questions are 1) what size should the return vent be? and 2) where should it be located? Our high efficiency furnace (96%) is about 6 feet away on the other side of the wall, so it would be easiest to place a vent there, but then it would be 5' below and 2' to the right one of the heating vents. Should it go on the same wall? Or is it important for me to go to the (whole lot of) trouble and lost space to snake it around to another wall? Also, 3) is two 6" ducts too much heat for the size of the room and should I plan to damper them down (perhaps the one closest to the return), therefore needing a relatively smaller return duct? Thanks for your advice.