The first time down the track I set the throttle cable-rod about half pull. Opening up a little more each pass, you learn more about you and the car till you feel easy makeing an all out pass. Very fail safe. I've seen one guy go full out on the first time out, did a giant wheel stand and come down hard, flip and totaled his car, ended up on the roof. The more HP the more unpredictable it is.
Might add, make your first settings soft, engine tune, suspension, then work up to the best, not on kill right off the bat. Learn your combo in steps.