Negative correlation on top finishers

Many golf promos on sportsbook apps must be a parlay. Since top finishers would be affected by negative correlation, the real odds aren’t the real adds when you add two or three to a ticket. Is there a decently way to approximate the decreased value on stuff like T5s, 20s and MakeCut?
I have just avoided these promos in the past, but wondered what the math would say.
Thank you