It really depends on what type car you have and how it's powered. If it's a fairly heavy (3000+ pounds), basically stock suspended car, running between 10-12 seconds in 1/4, I'd start with 0.990 instead of 1.010 and leave off the top bulb. The top bulb will catch you off guard for a while, so don't change your box setting until you can react somewhat consistently. Otherwise you'll just be chasing the numbers around and getting frustrated. The quicker and lighter the car, the larger the numbers will be. Let's say after time trials that your average rt is .050. If you change that .990 to .950, your rt should be .010 if you and your car react the same as in time trials.....good luck and have fun!!