Problem 1: Twinning Staff can cause a copy spell like Reiterate to copy itself infinite times and thus copy the original target infinite times.

Solution: Nix Twinning Staff or all copy spells? Are there other examples?

https://deckulator.appspot.com/ (rough approximation based on cards drawn by final turn)

If I need to ramp on turn 2, commander on turn 3, and hit 5 mana on turn 4: The 13th ramp card is added after the 39th land but before the 40th land.

If I need to ramp on turn 3, commander on turn 4, and hit 6 mana on turn 5: The 10th ramp card is added after the 39th land but before the 40th land.

If I need to ramp on turn 3, commander on turn 4, and hit 6 mana for a ramp card on turn 5: The 17th ramp card is added after the 38th land but before the 39th land.

So assuming ~ 40 lands, I should aim at 13, 10, or 17 ramp respectively.