Converter. Trans brake questions.

So again in a perfect world with the 3,500 stall And my 2 step set a 3,400, i could just hold the car at the light at 3,400. Correct? While foot braking.
Yup, as long as your breaks and tires can hold the car back. This will all make way more sense after you get it installed and screw around a bit. I'm no pro drag racer, so a lot of the guys on here can give you better advice on staging techniques, ect. I recommend going to your track for test and tune day, and bring a notebook. Write down everything (air pressure, RPM, shift points, weather, ect). Write down how each change effects your time slip. The last T&T I did we brought my friends GN that he had never taken to the track. We started with a high 12 second smoke show, and ended the day with a mid 10. We really didn't play with the car much. Mostly just him learning how to launch, keep it hooked up, and playing with shift points.