I run 32F / 30R almost everywhere, thru almost everything. I ride a light Gen 1 & I weight about 165 - 170 pounds.
Some people air down to as low as 22F / 20R for slower / dirtier routes.
With nearly the same identical sizes of nearly all of the available brands & tread patterns which are actually appropriate for the KLR rims, I don't think 'tire construction' has much to do with appropriate air pressures.
It is still about the same x square inches of tire carcass at the bottom, supported by x psi of internal air pressure to either allow extra flexing at lower/cooler speeds or resist flexing (heat build-up) on higher speed, hot asphalt. IMHO.
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