Your total weight is my body weight. i run 35s at 85ish with just me riding(no gear).
I doubt 75 for you would be bad.

I get the wider tire and lower pressure trend we are in right now and accept the premise behind the trend, but i also think that it can get a bit absurd. 60psi probably wont flat, but would it start to be a wiggly drag?

I would load up with those weights and try a few miles at each psi. No need for a 60mi ride or anything. 3mi and you will know if a psi feels too sluggish.