I have a few questions about calculating a 3-bet shove EV.

How do you estimate the frequency in which your opponent will fold? Is there a particular stat you go by?

For example, I was recently in a standard situation where, 3-handed (2 places pay), the button raised 3x out of his 30BB stack. The SB (17 BBs) folded and I picked up QJo with 10BBs in the BB. I shoved and lost to A8. Was this a good shove? The button is VP41/PR22 with a 40 RFI from the button stat over just 80 hands. He's opening wide from the button (maybe, the sample size is small), but how do I estimate how often he will fold to my 3-bet?

For my calculation, I assumed he'd fold 50% of hands and that when he calls with the top 50%, I'd have 38% equity, which makes this a +2BB EV shove. Are my calculations in the ballpark?

I know this is a really specific example but I want to learn how to do these calculations correctly so I don't get stuck making -EV moves all the time.

Thank you guys!