the main is 61 cards, and the reason for this is 15 lands in a 60 card deck was not enough but 61 lands in a 60 card deck was too much so im trying 16 in a 61 card deck, the change in percentage is small, but this is still what im running.
I've done this in other formats but in Standard (for instance) the nonland cards are much closer in power level than those in Vintage. While the percentage is indeed small, you are decreasing your chances of drawing your restricted cards like Lotus and Ancestral, which likely outweighs the potential benefits. If you decide to run 16 lands in 60 cards, I would cut Preordains for an extra Dack or JTMS...something to mitigate potential flood. If you opt for 15 lands in 60 cards, I would maximize the number of preordains in order to help hit your second land drop for Gush.
@letseeker The fetch should be fine.
Edit: I mentioned this in another thread, but I am a huge fan of Gitaxian Probe, especially in these decks that have multiple pathways to victory. Consider the following circumstance: you preordain into Tendrils of Agony and Monastery Mentor. If you Probed your opponent and saw a Supreme Verdict, you would realize that the Mentor is not going to be a great means to victory. This lets you bottom the Mentor and try to dig further for the storm kill. If you saw a Flusterstorm, you know it's going to be a rough Tendriling the opponent out, and you want to just slam Mentor with cantrips to win the game. Probe gives you the knowledge to optimize your line of play.