its definitely more complicated than that. a single appearance would not return B duke to A+. on the other end of the spectrum, a single NT appearance would take a D school with a D+ baseline (or whatever the worst baseline school is) much past their baseline.
baseline isn't this simple, but you can sort of think of it like this to answer your question. suppose baseline is 30% of your prestige, and your performance is the other 70%. under that model, you basically need the performance level on par with your baseline, to return to your baseline. this is probably roughly true. what it takes to hit a b- in d2 is roughly what it takes to get a b- baseline back to b- (such as a PI1 followed by a NT1). for an a+ school like duke, something like a string of NT2s/S16s would get you an A+ in d2, and that is roughly what it would take in d1. or something like a school who usually makes the NT1 or NT2, getting a trip to the elite 8.
this is definitely not a perfect rule of thumb, but at the start i was gonna say, there is no good rule of thumb i can see, but i think this actually gets you reasonably close.