[Tom Goldman]

All NHRA events are either a .370 or .470 tree so always start there for your baseline. you can always add additional delay for independent races that might utilize a ,400 or .500 tree .
If you already have a base delay for your car you can start with that and adjust the rollout to bring your reaction times into the area of your average RT'S on the track .
Typical roll numbers can be between .220 and .260 depending on class ,horsepower ,chassis setup, and launch rpm.
My own car has a rollout of around .230 . and I typically need between .030 .040 delay.
Once you have a data base of actual track runs to compare to practice tree runs you can fine tune the roll settings .
If you are using it with the full size tree , Allison Doll recently posted about the Portatree ,or any practice tree , that you should try to position the tree to be as far away as the actual track tree to get a more realistic reaction to the lights.