Personally, I'm using the TGM's recommended MDF of ~45%, wc means I'm folding ~55% (villain's actual RFE for his 3b is ~68%, but author reduces it to ~55% for the fact that villain has postflop equity). Obv, my MDF consists of flatting, 4b value, and 4b bluffs.

What portion (% wise) of your overall opening range do you defend vs 3b or you think is an optimal% defend?

Another concern of mine is when we get 3b by a known fish or tight players w/ non-optimal 3b freq (on a nitty 3b freq side) but using a standard 3b sizing (so their RFE is equal to decent players). Bc if we exploit them by overfolding, aren't they also automatically exploiting us? How should I think about this spot?

Thanks ; )