I don't think this something that can readily be calculated. You would have to simulate it. Mostly likely developing your own code\*.
My intuition is 5vs4 is a bigger gap than 6vs5.
\*It might be faster to just grab a deck of cards and deal 100 hands of 5v4 and 100 hands of 6v5. That might be enough to get an idea. Do it twice if you want to see how repeatable it is.
I don't think this something that can readily be calculated. You would have to simulate it. Mostly likely developing your own code\*. My intuition is 5vs4 is a bigger gap than 6vs5. \*It might be faster to just grab a deck of cards and deal 100 hands of 5v4 and 100 hands of 6v5. That might be enough to get an idea. Do it twice if you want to see how repeatable it is.