How to set max_history for long stories?

Rasa: 1.10.14

I have 4 different stories for 4 different use cases(scenarios).

Each story is about 20-24 lines (I added slots set by actions to stories as I was getting user warnings otherwise).

In all these stories, the first 15 lines are common and the following lines differ based upon the slots set by the actions in the previous steps.

How much max_history should I set in the config.yml?