DFGT with no clutch I use left foot, it's board anyways lol. When I drive IRL, I drive man and no choice really, left foot is dedicated to the clutch the right foot going back n forth from gas to brake.
When I drive an automatic IRL I use the right foot for both gas and brake, I have learned to keep my on street driving much more relaxed physically but alert mentally. The aggression comes out on the Track and transition speed becomes an important factor.
From what I experience emergency stops are two foot, manual, one on the clutch the other on the brake, in automatics, I see two feet on the wide brake pedal. Honestly though I can't recall if I've ever done a two foot brake stab on an auto because I've spent 99% of my time driving in manual cars, but I've seen it from the passenger seat. One time I saw a two foot grab it was my girl driving and well she's not that big not that heavy, I figured she needed two legs strength to get on that pedal lol.
With just a gas n brake pedal heal toe is not gonna be used, why would you?. Got me a lil confused on the comment of finding left foot braking faster than heal toe, when you heal toe BECAUSE the left foot is busy with the clutch, can't really left foot brake, if your left foot is dealing with the clutch, so you heal the gas blips to set revs for shift after using the tranny along with the brake to slow the car. I guess you can blip the brake with the left foot from time to time, but only when it's not dealing with the clutch (trail braking situation or lil blip here and there) when your gonna be shifting, the left foot is occupied.