Wanted to correct a typo ... happens a lot when you type on a small smartphone.
For the Max % play, you want to max IRR or Max (Exp EV / Initial capital)
first choice is (2X + 1X)/2 * payback
I made a mistake in the second choice: (2X + 3X + 7X)/9 * payback it's 7X because 7 lines have no X's and you are playing 9 lines.
Since X is a positive integer, then it's easy to see why the first choice is best for Max % EV.
Sorry about that and good luck
Welcome to the forum, and thanks for the great content and comments!