17 psi is not a huge increase in pressure while driving, in my opinion, though I don't claim to be a tire expert. I would generally expect the inners to heat up more than the outers, both because of somewhat reduced airflow around them and because they're closer to the brakes (and bearings, but bearings should not be generating much heat).
Reducing the pressure doesn't seem like a good idea to me, and may well be counterproductive, making the tires heat up even more. I understand it's always best to have both twinned tires in a dually at the same (cold) pressure.