I keep the spare at 50 psi cold.

We recently returned from a July 4 round trip from Western NY to Indiana, about 550 miles each way.  We averaged 60-65 mph and got 12-15 MPG.

This is our second major trip since having the trailer weighed.  We continue to pack only the lighter items (clothing, pillows, and sleeping bags) in the trailer and keep everything else in the van.

Carefully monitoring the weight is the only change I can attribute to not having a repeat blowout.  Since I had recently replaced the brake magnets and repacked the bearings, I monitored the tires and axles frequently as we stopped.  The tires by far are the biggest source of heat.

There happens to be 2 different brands installed and one tire runs significantly hotter than the other, even though both started out at 50 psi cold.

I am convinced on the 3023 that there is very little margin between the 'dry weight' (3240# on a CAT Scale) with options and the GVWR (3500#).  Doesn't take much to exceed the limit, and then you don't know how long you've got until a failure.