Strudeldog,
I have been told, and I have observed in my own rooted cuttings, that any wood above the highest node will eventually die back to the highest node. Any wood below the lowest node has potential to sprout roots, so it is viable.
One fallback to leaving more wood below the lowest node is that the cutting is hollow (pithy) and could be a potential area for mold/rot to take hold. I think it is for that reason that some people advise cutting the bottom wood all the way back to bottom of the lowest node.
My gut feeling is that you would want to leave as much wood on your cutting as possible...for energy reserves.
Have you rooted the cutting yet? That might help you answer the question of whether to put the node above ground or below. If you get lots of roots below that node, you could leave it above ground. If you don't get any, plant it below ground and the leaf shoot will find its way to the surface.
I'm too new at this to be a voice of authority, so I'd wait for some additional responses before making a decision.
Jim