I ran into something with my mothers ram. Here is the issue. The tires had a higher pressure rating branded on the tire itself. I went ahead and added more to the rear tires and brought it up to max pressure when we hooked up her 5th wheel. Well what do you think happened? Took awhile to figure it out but the TPMS in her truck didn't like it...and after a bit of travel the bells and whistles were going off. We finally figured it out...lol. So the lesson here is that the TPMS is set to what the sticker is on the door sill and not to what is on the tires. FYI...always check the pressure in your spare tire...it always gets forgotten.
As to the OP's question....I always ran mine max at 80...that is what was branded on the tire I used.