Didn't know Mills did sets or seed spuds, will have a look on Saturday.
The advantage of joining them is more volume/less surface area (or one less cold wall per house, if you want to look at it that way), meaning it should stay warmer. Oh, and one less door to open in the mornings!
I think I'm going to have one (16') side slabbed, to put staging on, and the other into soil for the toms. Does that make sense?
I haven't met GTG44 yet, may find that I know him when I see him. :)