Hi ! :)

Cobsidering you are OOP in a head's up spot and that at the flop you've to get flush or straight to get nutsed vs a top paired opponent and he barells you a X psb amount. With what precise amount should we flat his bet considering the pot odds but also implied odds ? We always talk about implied odds but we can't always expect him to push all his chips by the river. I know it's a complex question but in summary where can we considering him pushing his chips between simple odds (his flop bet) and all his stack (by the river) ? We have to figure out about our number of outs if we are in back door straight or flush, or in a draw situation. Is there a kind of équations modelizing this ?