There is no time component for the answer to the question, just a percentage value. Adding in the springs effect can be done later, if desired. For sure everything is changing
once the car moves, but it helps to have an idea of where things are at at the start.
Lets say the Cg was high enough to effect the needed force to lift the front by 6 percent, or some other number. A good chassis designer would be able to design the car around the intended ET, and launch torque for best results, rather than ending up with too violent of a car like I did due to setting my motor back too far or having the Cg too high, or both.