Maintain a static Parry rate while adjusting DEX.

What is your base Parry rate on X mob? (Fight it naked without any allotment - account for any Parry+ on your weapon; Make sure X Mob is always LV--)

How much DEX does it take to see an increase in your Parry rate? (Clear your attribute allotment and spec +1 DEX at a time until a definitive adjustment is observed)

Does monster level/family/accuracy effect Parry rate? (We need to account for the possibility that a monster's stats could change the rate you effectively Parry -> Monster Acc? - so repeat test on Y Mob @LV--)

Repeat this process with a static DEX rating while instead adjusting Parry.