Converter. Trans brake questions.

Couple things i have noticed over the years.
If a combo is pretty well sorted out, ET and 60 will be pretty much identical on a typical bracket car. No matter foot or T brake. Assuming hook.
My old 9 sec W5 deal would go 1.34 off foot or brake.. didnt make any difference. Usually more air off the TBrake

Another thing is people worry too much about getting the rpm’s up as much as possible using the footbrake at the track launching the car
Any car i have had, including my current car, i can leave at 1500, 2000, 2500, 3000 and the car ET’s the same. My convertor flashes 5100.
The only difference is reaction time. If i am racing on a pro tree i bring it up to 3000, if a full tree i usually leave at 2000, and sometimes will adjust my leave rpm to compensate what my lights are.
If i am too quick i will leave at a slighly lower rpm, too slow, slightly higher.
At the end of the day the car is going right to the convertor flash almost instantly. Playing around with lauch rpm has a tiny, but noticable effect on reaction times. I am looking for repeatability. I usually leave at 2000 just because its easier to see the needle on the tach, than at say 1800 or 2200 or any odd figure.
Anyhow, just my experiences.........