Most tyre companies publish tables to work out suitable tyre pressures once you have the weight of both axles. Often very different to the sticker the manufacturer puts on. Correct pressures make a big difference to fuel consumption and comfort.
The safest option is to go on a weigh bridge and get individual axle weights.
In the past I have emailed Continental and Michelin technical teams with these weights and tyre sizes. Both responded in a couple of days.
Save their response, just in case of any unfortunate insurance claim