Update: I went with trays, mainly because I had them and it took less time and potting medium. I put some potting medium in the trays, laid the tubers in them and then covered them up with more potting medium. (I use plastic pot markers to keep the names marked). The trays had no drainage, so I didn't water them, just put them on a rack in our barn until planting time.
When I went to plant them most had roots with some hint of growth to a few inches.
Bottom line, it worked, but I'd sure would have liked to give them more of a head start. Maybe next year I will have some kind of hoop house set up.
