IMO, pressure is the secondary consideration. Start by selecting an appropriate tire width, subject to your frame's tire clearance, then determine the best pressure.
If you look at the car and truck world, heavier vehicles use wider tires with almost no exception. If you go to the tire drop article, look for tires wide enough that optimum pressure is under 100psi, and consider these the narrow limit.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.