The last track day I ran I was at 34psi F, 30psi R hot. These are nt01 255/40/17 and 235/40/17 front. The car seemed to understeer a lot which surprised me because I've heard so much about snap oversteer on foxbodies but I did not experience that.
The car will snap oversteer in certain situations, but the primary handling trait is understeer. Running a staggered setup just added to that; I imagine the car will be significantly happier with 255s square.
Now I am thinking my fronts were underinflated and undersized because they are worn badly on the outside and my rears look relatively fresh. This is after 3 track days, apx. 60 laps on a 1.5 mile course. What is the optimal point on the sidewall for rollover? I noticed little arrows on the sidewall. Are they for rollover? Or is it the raised ring around the circumference of the sidewall?
The real purpose of the little arrows is to indicate where the wear bars cross the tread face; all tires have those little arrows (or something similar), look at your street tires and you'll see them. Folks do use those arrows as a guide to see how much they're rolling over onto the sidewall, but what amount of roll-over is "right" is a judgment call. An R-compound can almost certainly accept more roll-over than a street tire, but I'm not sure I would go as far as that raised ring.
Like Curt C said, I've found NT01s prefer a bit higher hot pressure, up around 40#. That's on my CTS-V (~4000# track weight, 275/35-18 R-comps), and is just based on feel and not based on tire temps (since I've never had a tire temp probe to play with).
Is optimum grip occurring when the tires are squealing? I'm starting to think I may have been just trashing my tires and not going any faster. After analyzing my videos it looked like possibly I may have been faster when I was not squealing around every corner, but it's hard to compare lap to lap because of heavy traffic on the course.
Depends on how much squealing and the tone of said squealing. In my experience, you start out with a lower pitched howl (as opposed to a squeal), which is good. If you push harder, you get into the higher pitched squeal, which indicates you're at or beyond the optimum slip angle. And if you push it even farther than that, you go back to a lower pitched grinding noise as the tire is just scraping across the pavement. I don't recall hearing anything in your video clip that made me think, "Whoa, he's really over-driving those tires."
Street tires are actually better at "talking" to you than R-comps, which is one reason why most folks say you should really learn to drive on street tires first. They have more gradual break-away characteristics, and they provide more aural feedback as you're approaching the limits. In my experience, NT01s are better with aural feedback than some of the more hard-core R-comps.