You should not be asking what others are using, but ask what is needed for your RV to drive savely for the tires.
I can calculate that with my motorhome-tire-presssure-calculator .
But need for that some information wich you can find on RV and tires.
For the tires I need Maximum load or Loadindex.
Kind of tire so Loadkind ( E-load/10PR for instance) to determine the pressure needed for the maximum load ( wich is not the maximum pressure of tire).
And best would be if you also give the speedcode presented in a letter ( N stands for max speed of tire 140km/83m/h)
From cars preferably weighed seperate wheel(pair) loads in the loading you ride with , second best is axle weighing , but in lack of those we have to do with the GAWR's ( gross axle weight ratings).
GVWR(Vfor Vehicle) is also handy .
Then the configuration of car like number of axles, and number of tires, front and back.
Then I will give a picture of my filled in spreadsheet wich gives high pressure-advices that still give acceptable comfort and gripp, but leaves as much possible reserve for things like.
Pressure-loss in time.
Little overloading in combination with unequall loading R/L.
Misreadings of pressure and loadschales ( even a calibrated schale has its inaccuracy)
Greatings from a pigheaded Dutchmen