The stats of playing lands at the right time.

I'm been playing a fair bit of Magic the Gathering and doing a lot of listening whilst on my walks.
I'm enjoying the challenge of improving myself.

When I first started playing over 10 years ago, I used to play with a deck that had a third of lands. When I started playing drafts in 2012, I was informed that a third was a little low and two fifths is what I should be aiming for.

I found that games were going much smoother.

As different sets came out, the requirement for how many lands you depended on changed.
I've tried looking at different sites for probabilities based on the number of lands in a deck but I could never grok them.
After producing my own numbers, I understand why. There is a lot to take in.

(or play with the whole thing)

This sheet allows me to see the number of lands I can expect in a given turn.
It should allow me to make decisions on whether I want to be sure I get to land X and what is the likely hood that I'll have more land in my hands than I need.
It shows me how one more or one less land affect my hand.
The thing that came out of the sheet that I didn't expect was, 'what does it mean if an outcome happens 10% of the time?'.
In a draft, you are guaranteed 6 games, with a maximum of 9. That means if something had a probability of happening more that 16%, you had to be prepared for it happening at least once during the night.
I was expecting to adjust the probabilities by around 5%. Swaying them closer to 15% seems a lot, but I'll see how I go.

Love a technical solution to a non-technical problem.