What PSI are you running

So I pulled a the trigger on a set of 28 inch mega mayhems. I took the quad out for a ride on sunday and we rode some decently rough trails, and noticed that the tires seemed very stiff and over the rocks compaired to the stock rubber. Im assuming it was do the the taller and stiffer sidewalls, to gain back a bit of smoothness over rough terrain should I lower some pounds out of the tires or soft en up the pre load a bit. Would the tires soften a bit with time?