Several years ago at a Valkyrie rally I met a guy riding a GL1800 with the Valkyrie's 180/70-16 rear tire. He liked the extra ground clearance, and the 70 series is much easier to mount than the 60 series.

I'm sure the Valkyrie tires have a load rating similar to the Wing. However, I remember looking at some 65 series tires online recently (forget which brand) and the load rating was significantly lower.