So i was trying to work out how i can calculate math for defending ranges vs various sizings and opening percentages. Once i have the technique for this sorted i will be fine to work it all out myself. I am stuck on the relationship between the preflop raising range and how that should affect my defending range. Of course theres the issue of hands that are flat called vs 3B, and how that effects our equity realised. Anway heres where i got to earlier:

BB Vs BTN min raise (assume SB folds).
Blinds= 1.5
Btn=2
Our call=1

We risk 1 to win 4.5 so 1/4.5=0.2222 so in theory we can defend 78% of hands

However since we our OOP so can't realise 100% of our equity so let's say we can realise 70% of our equity. So 70% of 78*0.7=54.6%

This theory is (I think) for a 100% button open. If button opens less we need to defend less bc they are letting us collect the blinds when they fold, but not entirely sure on this point and would be greatful if someone in the know could discuss it

That means if button opens:50% Range we need to defend:
50x0.78=39… 39x0.7=27.3% of hands

So am i correct in thinking that if buttons a tighter range we should defend less hands (seems pretty obvious but not entirely sure) even vs a min raise? I defend really wide and was surprised that math wise it seems i should maybe be folding much more than i am. I mean defending 27% vs a regs button min raise of 50% just seems crazy tight to me, i generally defend more like 60% of hands in this spot.