As long as your value hands are +ev when called, I don't think it matters if they can be outdrawn. It's still a value bet even if you don't have 100% equity.
This is how I do it, but it's not perfect:
(1 - equity of bluffs vs threshold bluffcatcher) = %miss
bet/(pot+bet) = alpha
alpha/%miss = alphie
(alphie*shove combos) = bluffing combos
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So if I decide that my bluffing range has 33% equity vs my opponent's threshold bluffcatcher, then in order to make that threshold bluffcatcher indifferent to calling or folding, I do the math:
1 - .33 = 0.67
let pot = 1 before I bet
let bet = 1
after I bet, the pot is 2.
bet/(pot+bet) = .33
0.33/0.67 = ~0.4925 non static game adjusted bluffing frequency.
When (value combos + bluffing combos)(0.4925) = bluffing combos, the opponent's threshold bluffcatcher will be indifferent.
From there, it's a matter of making sure that value shoves are +ev, and making sure that the bluffing combos on each side of the equation are equal, or really close.
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In game, I use a shortcut by estimating a % increase of static alpha and making an educated guess as to how much I should be bluffing based on previous calcuations. The more equity my bluffing range has against the opponent's threshold bluffcatcher, the more I bluff.
The result is a very minimal % increase on static boards, and a relatively high % increase on more dynamic boards:
I raise 3x on the button, small blind 3 bets to 10 big blinds, I call.
1) A72r small blind bets 20 big blinds and I shove my last 80 big blinds for ~potsized raise. Here, I'm only bluffing ~35% of the time because my bluffs don't have much equity.
2) K
8
9
same action, but here my bluffs have more equity because of the flush draws and straight draws, so I can bluff a lot more, probably somewhere between 45-50% of the time.
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It's not perfect though. That's just how I do it.