I think you need to tell us how much he 4-bet to first. Then you can calculate what he's risking to win in the pot, and then work out your minimum defense %.

Then if you consider your strategy is to never flat the 4-bet, but instead 5-bet jam, you can do the math from that point on.

wow 80% is really wide for 2.5x, i think its fine to include 88 here for sure seems like he also 4bets quite a bit so nh imo. Jam vs 4bet.

lets say he 4bets to 22BB. 

Open size: 2.5BB + 1BB (big blind)

3bet size: 10BB

4bet Size: 22BB

Risking: 19.5BB to win 13.5BB

MDF = 13.5 / (13.5+19.5) = 41% 

And yeah lets assume I never flat 4bets here, how do I solve for a correct 5bet jamming range? Thanks for the help Bdon

@ Daz - so if villains 4bet is 29% how is that KK+/AK? I appreciate the help dude

The bluffing portion of villain's 4bet range needs to be 28.3% for KK+ AK

Alright, so what i have already is a spreadsheet i created using the maths found in "Let Their Be Range" calculating how often villain needs to be 4bet bluffing in order to shove a hand like QQ+ AK - in the example, it was calculated that QQ is profitable to 3b/gii if villain has JJ+ AK in his AI value range BUT that AKo required some bluffing frequency depending on sizing of approx. 25% So basically i took their workings and constructed a table for most hands including 88. The spreadsheet allows you to choose bet sizing and then it calculates the bluff frequency for you.

But what we need to know is given the opening size of villain and his 4bet stats how often is he bluffing and what might be his value range? So i'm looking at this part now

Okay and what i am also using for reference is how DONKr constructed preflop GTO Ranges in his articles. In particular it showed how BTN may choose to flat rather than 4bet some of his lesser premium value hands. 

Using:

 -25/20 w a 80% RFI on the button and 43% F3B and 

-4bets 17% total and 29% on the button after RFI (over ~1.7k hands)

if we ignore sample size and stat noise and use stats as given then:

villain is calling/4betting with 1-43% = 57% does this infer c/f/r% versus a 3bet of 18%/43%/29%? 

From what GTO ranges i've constructed the ratio of call/4bet needs to be approx 2 to 3 which is almost exact at 18%/29% so villain is using the GTO methods used in DONKr or some equivalent.

With an 80% open and 30% defend to 3bet, villain would need 80%:
0.3*0.55*.8=0.132, 175 value combos, depending on 4bet sizing to 22bb 55/45 v/b ratio 27bb 60/40 b/v ratio .. so to 24bb lies almost in the middle so i would estimate a 57/43 v/b ratio, so with 175 value combos villain would have 132 bluff combos. 

But we still need to know what villain's 4bet/gii value range is, he may very well have 132 bluff combos but then flat some portion of his value range instead of 4b/gii

In the DONKr articles they simply made an assumption as to what reasonable shoving ranges were - they used TT+ AQ for a 35% open but didn't really talk about how do deal with much wider BTN opens. 

going back to how he constructs his 4bet range: 1326*.8*.29=307.632 and this is in ratio v/b 175.5/132 (a 57/43 would be 177/132 so numbers really close)

The bluff portion here is approximately 43% which when we look back at the table:  

88+, AQ| 35.8%| 38.4%

TT+, AQ| 37.3%| 34.6%

88+, AK |30.2%| 49.6%

TT+, AK |31.3% |47.7%

JJ+, AK| 33.3%| 44.1%

QQ+, AK| 35.8% |38.4%

KK+, AK| 39.4%| 28.3%

KK+ |19.3%| 62.7%

Means we need villains 4bet value range to be 'in bold'

So if includes AQ in his BTN AIPF value range OR is quite tight 88 can be played proftiably with a SHOVE