Hey Jaybar,
to the site.
I am not sure that I can be a lot of help since I am just moving into the area. I am more familiar with NCCC events than other sanctioning bodies. Here is a link to the NCCC clubs in the Florida Region.
http://www.ncccsouth.com/FL_Reg/FL_C..._florida_.html
It sounds like you are more interested in high speed events than autocrosses. There tends to be more autocrosses scheduled in NCCC than high speed events due to the costs of renting a racing facility. But here is a link to the upcoming NCCC speed events in the south (NC to Florida). By attending a few of these events you will come into contact with some serious racers and they can lead you to what you are looking for. I noticed that there is a high speed event coming up at Roebling Roads in Georgia.
http://www.ncccsouth.com/Events/events.html
Check the event flyers and call the people running those events and I am sure you can find what you want.
As far as setting up your car, I am sure from running your Stangs you are aware that set up is dependent on the car, the track, the weather, etc. I can only give you a guess at tire pressures on a stock Z06. I ran the North course at Pocono in April and with the stock setup and Goodyear SC tires my pressures started at 32 (front) and 35 (rear) pounds cold. After a 20 minute track session they would grow to about 39 pounds. Once my pressures built up above 39, the car got loose and I had to pit to adjust the pressures. I added the tire pressure sensors to my Z06 wheels just for this purpose.
Well, I hope this helps a little. Good luck in what you are looking for.
Rich