I generally don't air down but a mate road my Vee on gravel the other day and he preferred the feel of the E-07's at around 30psi. I wouldn't go any lower (and will be pumping them back up before I head out this weekend) as I got a puncture on a near new K60 when riding over rocky terrain on the one occasion I did experiment with lower pressures. These bikes ain't light...
'08 Vee: Suzy luggage, Crash bars, Rad Guard & front mudguard extension, Zumo 550, Oxford Hot grips, Stebel, PC-8, 12v acc, Scott oiler & lube-tube, Remus Revolution Cans, Bark Busters, Phillips Extreme vision +100 bulbs.
'08 Concours 14: Rad guard, Stebel, Oxford Hot grips, Projekt D Screen, Hugger, GPS mount, helmet locks & front guard extension, Zumo 550, Stebel, Phil's rack & Givi V46, Sheepskin seat cover, Phillips Extreme vision +100 bulbs.