I'll add my experience. I've got a 550 with non-adjustable clubmans and I've taken pretty long rides on it, +200 miles. I can feel it in my lower back, but ab and lower back exercises help, not to mention shoulders. I'm right at 5'11", 32" inseam, and about 192lbs. After the long rides I think my throttle hand is the most noticable bother, it gets pretty buzzy. I think a lighter throttle return spring and a bar end weight on that side would help tremendously.