MTV
I think those 10" adapters that you mention used to be made by Gar Aero. And have since been bought up by some outfit in Alaska. I was looking for their name, but couldn't locate it. I have talked with them and they seemed nice enough, but I have heard of people having rare problems with them coming apart.
I may be wrong on this, and will probably find out soon if I am, but Wup has a new 10" 1 piece wheel, and I think that would be highly preferred over the adaptetrs I have never seen adapters in his catalog.
That being said, I would think that it would be better(for most, not in extreme backcountry terrain) to run the smaller wheel with a large tire, giving you good energy absorption, less weight and less lateral stress on the equipment if you get a little sideways.
Just my thoughts G