I like to "break"the tires in.Not sure if it really works but I haven't broke a belt yet.
Since you went to 30# next time take them to 25# and then the next time 20#.I wouldn't go much lower with the 265's because the tire will want to roll around alot.
After 20# you'll loose alot of ground clearance and since each tire/wheel combo is different this will give you a chance to experiment.
Don't drive hard/fast at lower pressures because theres more chance for a rock to deflect into wheel at impact and possible cut the sidewall as the tire get's pinched.
Goodluck and welcome to the board.

Bansil