Eric, if you have plenty of grip on the track surface or with your tyres, try using the stock plastic 0 degree rear hubs.
They will make the rear rotate quicker when you come into a corner/give you more steering, should give you a bit more top end, the trade off is a lack of straight line stability.
You can adjust the front to have a bit more toe out to gain some stability back.
I have used 0 toe on a grippy track in hot weather and it worked well, but most of the time I just use 2 degree plastic toe in, or 2 degree alloy toe in.

As you mentioned in your post, there is definitely a sweet spot in regards to camber. Some tyres it's 1 degree negative, others it's 2 degree negative, or anywhere in between, it's something you'll have to play with to get right for your tyre and track conditions. If you're using the adjustable upper links on the rear, even a 0.1 or 0.2 shim can make all the difference in finding that sweet spot.