You could probably get away with five or six utility lands
Gwaihir, Greatest of the Eagles and Mirkwood Bats help to threaten your enemies, along with rewards for gaining life such as Gollum, Obsessed Stalker and Sanguine Bond to outlast any opponent
To help you play the most absurd cards, here are the ten best ramp cards in Commander
Chaos Dragon Chaos Dragon is a 4/4 flier with haste that needs to attack every turn hardly a downside since you want to, anyway
The only deck I'd run Mirror March in would be the Coin Flip deck where we can dramatically increased its power level with the help of Krark's Thumb, aka Zndrsplt, Eye of Wisdom and Okaun, Eye of Chaos
So then you have to think about whether you want to commit to the board to force them out of developing their hand, or whether you think the card you want to deploy is too important for you to jam right into counter magic