This is like trying to measure wind. You can measure the direction, velocity, strength, consistancy, opacity, and all kind of other factors but what have you accompolished. Non-quantifiable factors enter into stopping power in my estimation. I don't know how you measure these factors such condition of stoppee's nervous system at time of impact.
Determined to kill you, wants to kill you,might like to kill you, just making an effort to kill you. This sounds silly I know but without this type of data you can NEVER make a determination. You can make all kinds of educated guesses but in the final analysis it's still a SWAG.