I have them on a '99 Tourer which is wearing an I/S trunk and tank, Memphis Fats fairing and assorted safety chrome/electronics/communications gear. Figure roughly the same weight as an I/S.
40 front; 42 back.
Any more than that in the front and it wants to weave. Less and the steering feels somewhat mushy.
The rear gets adjusted up slightly if I'm riding with a passenger but the ride is rough at higher pressures without one.
As always, YMMV. Mine's right at 41mpg.
