I have GT3 control arms on the front of my 08 Cayman S Sport and front camber set at -2.3 and rear at -2.0 with stock setup. I initially had -2.5 on the front but that wore out my front tires way too fast. At -2.3, I can wear out the fronts and rears about the same time - approx 15K mi. Usually you buy two rear sets for every 1 set of fronts.
Since you are just beginning to do track days, here's what I'd suggest:
Have a race alignment done with your stock components. JayG says it won't amount to much and he should know. I haven't had a 986 for 16 yrs. But for your situation, even -.75 will help and may be enough to save your tires at the track and on the street.
But that's where I'd quit at car mods. If you're just starting out, your car is going to be way more capable than you are. Focus on making yourself better as a driver before making lots of changes to your car. Don't worry, you can spend as much $$$ on driver improvement as car mods.
First thing to do is buy a GoPro. It doesn't have to be the latest / greatest. You can prob buy a 2 or 3 generation old GP on fleabay for a cpl hundred and it'll do the job. Put it over your shoulder so you can see what you're doing as well as the track. You will be surprised by what you're actually doing vs what you THINK you're doing. I'm a visual learner and this was what I did to make huge improvements in my driving. Even now I still watch my vids to see where I can make improvements.
Consistently drive the proper lines thru EVERY corner. Many times a novice will have 1 or 2 corners that they totally blow almost every lap, even tho they've been taught the proper line. Work on getting those corners right and your lap tmes will drop substantially. While "perfection is unattainable" (Tin Cup ref), focus and concentrate on doing an entire session w/o any mistakes.
Work on being over to the edge of the track at turn in, not a car width or more from the edge. Then accelerate thru the apex all the way to track out. Will this make a big difference? Maybe a .10 faster, but if you have 10 corners and my math is correct, that would be a second a lap faster overall. That's substantial. By accelerating all the way to track out, you get that little bit extra speed vs cutting it off in the middle of the track. And as a wise driver who used to frequent this website told me once, "they put track out there, you might as well use it".
Are you monitoring tire pressures during the day? If not, you're loosing time as well as prematurely wearing out your tires. I wrote an article about how to find your ideal pressure. Pg 19.
https://www.gprpca.com/wp-content/uploads/2023/06/DerSkooner-07July2023-FINAL.pdf
Seat time is also important. Do more DEs. Just be sure when your on the track, you're doing the proper things, not enforcing bad habits.
Work on yourself before you start making lots of investments in your car. Right now the only money you should spend on your car are mods that make it last longer rather than go faster. If you focus on the items I listed above, you'll only spend $150 for an alignment and $200 for a GoPro. That $350 and the suggestions will take you a long way towards making you a better driver.
Here's a vid from my last DE. Notice the wild lines some of the drivers take.