is it standard to 3bet vs btn in sb with 3card hands, along with 3card hands in bb when sb folds? i don't really know how to do the math of counting % of villain 2card-vs 4card and pat hands.
also, what 3card hands are playable when we are coldcalling 4bets? i'm thinking just 234 and 72w's?

I would guess that three betting a 2 cd draw is probably pretty player dependent. Err on the side of flatting and don’t sweat flatting full range. My guess on flatting 4 bets is that it shouldn’t be done without a deuce + wheel cards not containing a six

Many players I respect greatly advise flatting full range but I really disagree with that notion as it probably leaves way too much money on the table.

Suppose we have 237 in BB and face an open from the button. No one will argue that we have an equity advantage over this range but for the sake of information hiding they suggest we should flat our entire D2 range. That's fine, my counterpoints are the following:

1) We are calling with hands like 743 and 754 against a button opening range that really only has a deuce around 60-70% of the time. So many deuces are left in the deck so a hand that calls can make a very strong hand a lot.

2) You may also choose to call 237(KQ) but re-raise 237(33)

3) This is a limit game, think you need a very good reason to constantly turn down putting in bets as something like a 3 to 2 favorite over a range for sake of information hiding where benefits of that may be negligible.

The main drawback is that you are OOP and the IP player will win more than their fair share of pots due to this advantage. But that is tough to quantify and probably does not eliminate the equity edge that you are turning down. If it was PL 2-7 TD it would be a different story, but in limit you will realize your equity enough of the time.

In addition, many players are exploitable in spots on the turn where you are D2 and they are D1. So you can build that pot up and take away more than your fair share anyway.

Unquestionably there are ways to improve on the simplistic approach I suggested. However, when in doubt or when new to the game it strikes me as a pretty good rule of thumb

Oh I wasn’t picking on your comment

As I mentioned I’ve had this debate with other mixed players and I know others that adhere to this

Never took it that way at all and wouldn’t mind if u were picking on it. If people are helping me get better at poker they can say whatever the f$&%* they want😁