Seems like you are referencing 2 lights. The pre-staged light has nothing to do with your ET, because you can't leave on a pre-staged only light. It's the staged light. It's only the amount of tire that determines when the "staged light it triggered", and "when you left the beam". So, you can shallow stage to where you barely trip the stage light or roll into it till you have left the pre-stage beam which is staging deep. That distance is determined by the tire diameter and inflation. OR..... Put some low-riding fender skirts covering the front tires that go all the way back to the rear bumper and get a 17 ft rolling start! :D
