"Touchiness" can best be remedied by skewing spring settings a click or two towards understeer; i.e., if a car with 13.1/13.2 springs is too whippy, go 13.1/13.1 or 13.3/13.2. If one click changes things too much, you can try the same thing with the dampers, drop or raise bound/rebound at one end and it will be slightly more over- or understeery in transitions. For the formula (I didn't realize how complicated it might seem) what could be easier than leaving the front at default and jacking the rear all the way,except, maybe...not changing anything at all.
Don't worry, the same thing happened to me during GT2. I was posting tunes on a forum very similar to this, well reasoned, logical and tested tunes; and some guy was posting "raked" tunes that are quite highly received. I challenged him about the awkwardness of his tunes, how they were counterintuitive and mocked low center-of-gravity tunes and blah blah blah. He politely replied that there seemed to be some measure or credit for air pushing down on the body and he was simply using what worked. I eventually had to convert all my tunes to canted because they WOULD go faster, but I never figured it out, I don't think he had either.
Then, while working on high speed instability issues with my Lotus Elan, I mean, a Lotus should be able to go 140(mph), no? I read this article:
http://www.mulsannescorner.com/techarticle1.htm
and specifically, this paragraph:
Bottom line is, the game physics engine makes provision for chassis downforce and it does not seem to penalize for c.g. issues and cornering dynamics that might be typical of a raked chassis.