avvidclif1 brings up a good point. Before everyone get carried away trying to dial in their precise pressure for the exact weight of the trailer have you considered each tire has a different weight?
While we may not know the weight of each tire. I think we do know each tire does not carry the same load/weight. With that in mind is it beneficial to air them to the same specific pressure if they are not carrying the same corresponding weight.
At the end of the day max. PSI is as an effective method to air the tires as any. It is also a lot simpler. Keep an eye on the tires to ensure they are wearing evenly and adjust accordingly. It's really not that complicated....No charts required.
I purchased my Sailun's because I wanted extra capacity not exact capacity.