First you have to understand what is going on.
You are traveling in Feet Per Second.
The longer it takes you to get to your maximum braking capability,
the more time you spend traveling at a high speed in
feet per second eating up valuable distance between you and a solid
object.
In a collision avoidance situation where I can brake in a straight
line , I nail the front brake hard enough to lift the rear wheel or
until I feel the front tire slide a bit or steer funny. Then I worry about
backing off of the brakes a bit to straighten the bike out again.
Bang a downshift or two.
In the wet or on a curve, its both brakes for sure.