I'll tell you what I do, and what I most often hear about trailer tire pressures. Inflate them to the maximum pressure as specified on the tire sidewall when the tires are cool, that is have not been driven on and have not been sitting in the sun for a long time. Once you set this pressure, don't bleed them down as the pressure builds up during the day.
The maximum pressure on mine is 65PSI; the actual pressures vary from 65 when starting out a driving day to as high as 75PSI when driving on a highway in the sun with outside temperature of 100 degrees or so. My TPMS is set to alarm if a pressure goes up to 77PSI, but his has not happened, so far.
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2008 Chevy Duramax; Pullrite Superglide Hitch