Understand that using either brake while cornering will only modify your trajectory by increasing your radius (standing the motor up) and generally will NOT allow you to tighten the radius.
Don't EVER forget the friction circle. The more you lean the more cornering force that is produced. This combines with whatever braking force that is applied (Pythagorean Theorem) and both use up whatever braking force that is available. So let's say on a given level surface you can produce 1.0g braking force. In the next corner you lean 20°. You are now utilizing .364g of your available friction (tan 20°=.364). Now you have only .636g of braking force left (1.0g-.636g) before you exceed the maximum friction available and complete the corner on your ass!
The graphic is actually shown upside down, as deceleration is negative and should technically point down.
You are progressing up and lean 20° into a right hander. If you brake you have ONLY .64g left for use.
Hope this makes sense?