A bit late maybe, but here my two cents:
My wife and I travel on two Africa Twins, not the lightest I know...
We are roughly equal considering length etc, so we have the bikes in a roughly similar setup.
Maybe this is not perfect for the person riding his/her bike normally, but it does make it very easy to swap bikes when you need to.
e.g. when we were in Bolivia, playing in the mud for a few days above 4000 meters altitude, Mirjams bike ran on one cylinder. We swapped so I had this issue to fight with, and Mirjam drove my bike through the mud for 3 days. I think it is very nice when the other bike feels natural to you when you have to drive it!
maybe something to consider.