Count 2 is quite short. This can be measured. Take a timer, start with your hand in a firing grip, and on the beep, draw to retention and fire a shot. Subtract your reaction time (usually around 0.25 seconds), and that gives you the length of time it takes to complete the entire Count 2.
I did this experiment today. 5 measurements, average length of time to draw was 0.59 seconds. Assuming my reaction time is 0.25 seconds (an optimistic, but occasionally reached, estimate) that leaves 0.34 seconds for Count 2 to be completed. Probably means I am giving up less than a quarter of a second to wait and fire from a stable, repeatable and practiced index.