I did change camber and toe, plus pressures, did not change caster. I let tire temps dictate the changes.
This is a bit of a digression as most of the Hoosier VFF shod cars will be the original FF's from the 1970s, but as some clubs are now allowing CF cars this discussion will be relevant for some.
My thinking is there are three principal points of compliance between the car and the track, with varying degrees of said compliance. I see them as the frame, the shock/spring package and the tire carcass.
In my case the car was set up with a stiff frame (significantly improved from original with the addition of anti-intrusion bars and other stiffening/additional bars), a stiff shock/spring setup (Penske 2-way, B/C valving, 350/300 springs, essentially Crossle 35 geometry) and in the case of the Hoosier a very stiff sidewall.
I have asked Hoosier about tire spring rates but have not gotten an answer.
I had to increase the shock settings way higher than what I normally use with American Racer AR133 tires to control the unsprung weight from chattering from the minor undulations of the track surface. I would normally run the shocks about halfway of the settings (3/6 bump, 12 of 24 rebound) but had to crank the shocks up to 5/6 and 4/24).
My thinking is the AR's would absord the high frequency low amplitude undulations with their soft sidewalls whereas the Hoosiers would just transmit them through. So I think I need to put some compliance into the suspension, in this case lighter springs being the first step. I'll control the subsequent roll with the bars.
The fast CF (Crossle 35?) of the two vintage weekends was using very soft springs, much softer than commonly used with AR's so this has supported my thinking to some degree.
If my thinking is correct the Zink may very well have the compliance needed built into the frame by default.
Tom