So whats the deal with frames 9 and 10? Are they empty? Is this 8 frame? If it is 8 frame it sounds like it is full and you need a second box. I just re read and see you have empty frames on one side. Remove two of those frames of honey and slide the rest of the frames over to that honey side and put the honey you took out on the other side. That mass of honey acts as a good heat sink to help keep the cluster warm at night. If this box you want to add is a deep and all foundation, I would believe it or not put it on the bottom. Your bees are about out of room but not populous enough to do much with a second box. The empty on the bottom will put them further away from cold air and the bees will move down if they run out of room. When the top box is ten frames of bees, then put the second box on top. That is the way I would play it. Best of luck whatever you choose and one more thing! No need for another full inspection for a couple weeks or more.