6psi is not low for that tire at all. If you had an issue before, it likely wasn't due to pressure. I would be more concerned at close to 10 psi where you run them. That's overinflated and can be sketchy. I am obviously not implying anything towards you here, because you have been running big tires for years.........But SOME guys get uncomfortable with the big tire "waggle" in high gear. Meaning the car seems to float around in the rear. That's normal and cars just move. The problem arises when guys attempt to correct every little waggle and before you know it, the car is all over the track. Just keep it pointed straight, let the rear sashay a little and she will go right down broadway.

That's a tall tire with a lot of sidewall on a 15" wheel. You get it stood up in high gear and the tread pattern is narrow with a lot of rubber between the rim and the track. It's going to move around. Overinflated, the tire is too tight, the contact patch gets tiny when stood up. It may "feel" more stable, because you have it pumped up tight, but get it in the marbles and it will be out from under you before you know it, because there is no rubber on the track and the tire can't recover.

Hard to say where you should start on the shocks, because I feel certain they are done. I would run the shocks through some sweeps, then tug on the quarters and see if the adjustments actually DO anything. If I was setting this car up from scratch, I would go 6" on the bars from the wheel center, 6psi on the tires, 80% tight on extension and 50% on compression for an initial hit. Not knowing condition of shocks makes this all a crap shoot at best on settings though.

On the front, I would pretty much guarantee the fronts can't control the rise, so I would try them full stiff on extension. You actually WANT it to make too much wheelspeed early and kick the tires.........then you back it off. Since you have data now, you will be able to determine if it just started out TOO hot, or it stuck the tire, bounced and THEN got hot

Realistically though, I doubt you can make that car too hot. It just doesn't have that kind of power. I mean my GTX was a 3200lb ladder bar car with 29.5s. I left on all I could make and it went high 1 teen 60fts. I could go 1.24 on a bowling alley with worn out hides. You are lighter and a much bigger tire. I simply can't see it overpowering that tire