jatrax,
We have different PC models, you with a 2552 and me with an old 2350 so keep that in-mind. Yet I think much can be applicable.
Our 2350 is of the earlier design where the fresh water tank is butted across the rear wall.....the worst for weight distribution, and because the water sloshes side-to-side, it affects handling. Amplifying the situation is our 158" wheel base. We successfully addressed the handling issues with aftermarket suspension upgrades, but the tire pressure remains a gray topic.
The PC sticker on our driver door frame states 65psi front, and 60psi rear(65/60). After weighing our rig loaded up on a big trip, the Michelin charts recommends the same psi. So at least we have that consistency.
My concern is the when I put the recommended 65/60psi, it looks like there is not enough air in the tires. They look under-inflated with significant bulges where the tires meet the road, the rear tires worse than the front. I have to add 10 additional psi 75/70 before the tires look right, but doing so roughens the ride terribly. So like others here, I too have added just 5psi to the specifications 70/65 as a compromise. Sometimes I run 65/65 depending on what we bring along.
I think you are doing great having only a 275 pound difference between one rear corner and the other. I don't know what our corners weigh for I weighed just the axles, but I anticipate a significant difference given the placement of our fresh water tank and outdoor storage compartment. One thing you don't want to do is have varying tire pressures within an axle. Take the worst case rear corner and make the other rear corner psi match it.
When you figure it out, be sure to educate me
for every we leave home, I feel I didn't get it right yet again.
