Found your tyre on internet in standard load, loadindex 97/ maxload 730 kg AT 2.5 bar/ 36 psi upto 160kmph/99mph.
XL loadindex 101 / maxload 825 kg AT 2.9 bar/ 42 psi upto 160 kmph.
So look that up at sidewall .
Did not find a C-tyre in that size.
Then you could calculate lineair the needed pressure, if you determined the axleloads in your use.
But I can make a cold pressure/ axleloadcapacity-list with build in maximum reserve, at wich comfort and gripp is still acceptable. Calculated with my determined formula, tighter then the official european, closer to lineair calc.
For that I give 90% of calculated axleloadcapacity, for max 160 kmph/ 99 mph ( fast enaugh I think) .
Is the same as adding 11% to the 99% acurate determined axleloads.
Then give if wanted in kg or lbs, bar or psi.
To determine the axleloads is your responcibility, and the most tricky partin it all . Best would be weighing loaded as you drive
Carmakers use for fully loaded the max permissable axleloads and max technical carspeed.
But if you search and give here next, I can help you with dangerously estimating them.
Max permissable axleloads and vehicle weight, empty weight and most likely motor in front, and the way you load it with also the persons ( or animals), for the different situations.
