Ive run N/SS and Open Comp off the foot brake. Using bolt in the throttle linkage, weight, and reduced timing. The bolt was great in my old car. Fine thread 3/8”. Never had a bod. And it shouldn’t. You’re not moving the throttle far enough to affect pump shot. Within its range we could move the car .01-.02. If you get the bolt turned far enough ET will fall like a rock. Don’t go there. Method #2 add weight and then fine tune with the bolt. Problem with this is if it’s a multi day event and you get a large weather change it’s hard to hit the number first out in the morning. Method #3 weight. Put the weight in the right location and it’s really accurate. Problem is if you have to kill over .20 where do you put all that weight? We are talking 200 lbs plus of legally installed ballast. And yes we get spot checked.. #4 reduce timing, fine tune with weight. Problem same as #2. Large weather change can move the car more than you think. You need to know your car vs weather history. Not just looking at the weather station either. Been doing this since the 90s. If we are off more than .002x it’s a big mistake. This is with no starting line rev chip, air shift, or any other help. Pro tree going deep works well. Been attacking the Pro tree the last year just like the full tree, shallow. Still a little slow but getting there. By all rights a .500 pro and full .500 should be the same. I can do it in practice with in .010. Just need more hits in the car on the Pro tree. I have maybe 20-25 pro hits vs 25 years on the full tree.
Doug