Yes - I plant them at the bottom - with the baggies, I just sprinkle in a little soil mix, and the put in the tuber, then cover that with the soil. When the sprout emerges, I add more soil to cover it, until the quart sized baggie is a little over half full, then I finally let the sprout emerge and put them under lights. I did pretty much the same thing when I was using pots. One of the reason I didn't like the pots was that they all taper, so only really small tubers would fit at the bottom- I was chopping off a good part of my tubers to get them in there, which mostly seems to be ok as long as the roots hang started growing from that end yet.
When you plant them directly outside they go about 6" deep, so I have always figured I should plant them as deep as possible.
I suspect there are a lot of ways to do this successfully.
