Ride height doesnt change traction but the relation of the front and rear ride height does effect balance because of weight being distributed differently. For instance raising rear ride height puts more weight toward the front giving the feel of more front traction.
A car has more traction when it rolls more in the corner. Its kinda the same theory as above the roll makes one side lower then the other and weight transfers and weight on tires gives traction. Changing sway bars is an often overlooked tuning option that is highly effective. When traction is low softer sway bars or even removing one (probably not good to remove both) will give a good amount more traction. Its usually the first change I make after tires.
As far as roll centers go I am still a bit confused after 12+ years of competitive racing. I dont even know which way I am going when I make an adjustment but it seems like lowering the inboard mounting position makes the car more forgiving and less likely to traction roll and moving the inboard up gives more traction but can make the car feel twitchy.