So many factors involved - suspension type and geometry (IC), power/torque, stroke, gear ratios, tire type, car weight, stick vs. transbrake vs. footbrake, track prep....

All of these factors determine what the housing is going to do when the torque hits the pinion, the shock controls how fast it's going to happen.

Rebound affects the initial hit, bump affects what happens after that initial action. These affects can be observed by videoing with at least 30FPS, 60 is better, and watching it frame by frame. Much of what you want to see happens before the car moves a foot or 2.

My advice - run the shock as tight as you can. Some tracks can be rough to the point where tight compression settings will upset the car, and the settings become a compromise. High and low speed adjustable or electric shocks - where they are tight initially, then are softened after the car leaves the starting line - are being used more by fast bracket, pro tree guys these days.