No mold at all. The key is to spread the water, don't let it pool.
The only time I am even concerned about mold is when my snakes are constantly in and out of their soaking bowls and have created a puddle of water. Then I change the Cypress out in that area.
No humidifier at all. I've never used one, and see no need except for maybe reptiles needing 90-100%.
That's the big benefit of Cypress, it is at the top of the list for humidity control along with coconut products.
Now if you have a tank, and are having humidity issues, even with Cypress, then layering Cypress on top of Eco-earth is as good as it gets. I had no problem getting humidity in the 70s by layering and pouring double the water. The excess water drains to the coconut and then the coconut releases water to the Cypress when needed. Never experienced mold with a few years of that system.
Esmarelda, Jungle Carpet using the layered substrate.