Trying to learn

[Marcus SC&C]

There really aren`t any aspects of a front suspension that you can discuss in a vacume. All of the aspects interact with each other and you need to find the best compromises. Ball joint axis inclination does have a huge impact on scrub radius and it also allows some negative camber change when you turn the wheels. It`s not very much until you turn the wheels really far but considering how backward the camber curves of most traditional muscle cars are it acts as at least a small bandaid.
Caster gain is primarily a side effect of anti dive. Angling the cross shafts of the upper A arms (front side higher) in side view reduces front end dive under heavy braking. In factory cars with soft front springs/shocks that was fairly important,especially since many of them have extreme bumpsteer with toe out in bump. If the front end dives a lot the car gets very unstable. The additional + caster gain may also help to offset that unstability. In modern performance cars (or properly upgraded ProTouring cars) with firmer suspension and good (or corrected) bumpsteer you could do without most if not all of the anti dive which would also greatly reduce or eliminate the + caster gain. Mark SC&C