I did that one spring. I laid my tubers on their sides in a shallow pan with maybe 2" of moist soil. They were on the dining room table so also got sun though I guess they didn't need that. Might have been better to just leave them in the dark in the garage and just check them every day or so for sprouts. As a couple produced sprouts I nipped them, put them in rooting stuff and then into tiny little greenhouses I made from clear plastic cups, one bottom and one for the top. They had holes in the bottoms for drainage (I really soaked the soil) and the top kept the plant very humid. I got several really nice dahlias from them and they bloomed that summer. But like you Geof, I simply don't have the room for all the tubers, plants, plus other stuff I am growing in spring like vegies. It would be great to have the room to have say 3-5 of each type in a cluster, then swaths of them around the garden. Sigh. Ain't going to happen in this lifetime.
Only got a couple of dahlias added to my list. Got distracted by pictures I had taken in 2014 and 15. So nice to see green plants and flowers where all I can see now is ice and frozen ground.
Shoot. The whole point of logging in was to ask Arlene and all you north eastern people how you are doing with the snow. For all the headlines I keep seeing I don't hear a lot here at ATP about snow storms and disaster.