Bob – Either you misunderstood the guy at GoPro Motorplex or he’s in the weeds. You are correct that using that theory – and all things being mechanically perfect – he’d want the staggered tire on the LEFT side for that course.
Also as you most likely know by now, TJ is a great source for information.
Regarding tuning with air pressure: I “once upon a time” scaled my kart to find it had a slight twist resulting in a higher diagonal weight. At the time I thought I’d see what air pressure changes did to effect that. I balanced the kart using air pressure, then went out – ran 10 laps or so – and blistered the rear that was on the heavy side. Rookie mistake. I’d never blistered a tire before, nor have I since. But what I learned was use tire pressure to fine-tune the handling, not compensate for a mechanical imbalance. Better to address the mechanical issues with mechanical solutions in order to get your tires where you can fine-tune the handling. In this case, measure the tire circumferences and match like-measured sets together.
I will say this, I’ve had very good results running different pressures left-right depending on the number and direction of turns. At GoPro Motorplex, I start with .5 pound more cold pressure on the right (Bridgestone YLBs).