That was why I considered the Darkside myself until my insurance company wouldn't cover it.
The guy who changed my tires today said the wear looks like under inflation and suggested 44 on the rear and 42 on the front, especially since I ride 2 up 90% of the time.
His comment about the C109 and M109 were that "with passengers, those bikes eat tires fast, since they have so much power and weight"