Hi guys, i understand the concept of MDF%, what im struggling to understand is how to apply it at the tables.

let's put a simple example, hero opens in MP to 3bb  BTN 3bets to 9bb. BTN is risking 9bb in order to win 3bb + 1.5bb + 9.     9 / 13.5 = 0,66.  So we need to defend at least 33% of our opening range.

lets say that our raise 1st in MP is 15%, theoretically we need to defend at least 4,95% of our range.

now in example A   BTN is a 9/8 nit with 1% 3bet

          example B  BTN is a 60/40 whale with 50% 3bet

Both of them 3bet to the same sizing, theoretically we need to defend AT LEAST 4,95% against both of them when they 3bet us. But while defending that range against player A is a recipe for disaster, defending that range against player B is rather too tight. Against player B we just defend wider, but how about player A? i mean the best way to go here is to be exploitable and defend less than we should.

How does MDF% matter when a mega nit bets the river to 1/3 pot forcing us to defend x% of combos when we know that he's never betting nothing but the nuts?  i mean MDF is based on bet sizes and pot sizes but it doesn't take into account player tendencies.

Hope it's clear what my doubt it :D