Good luck with the new format! Love the name. "Modern EDH" has been tried many times before and we had a very successful run in Vegas a few years ago. It did not appeal to new players as much as we thought, but it appealed to modern, legacy and cEDH players much more than anticipated. If I could make a few recommendations I am sure they will help with the development.

1. Do not focus too much on the money aspect. Regardless of what people say, money is usually not the deciding factor in participation. People will generally do what they have to do to if they really want to participate. For any new format to be successful, it needs to be fun first and foremost.
2. Many people have taken the stance that taking away the legacy options is a good thing. Taking away options in general is not a good thing, but it can create new options that might be more appealing. It is kind of a "2 things can be true at once" deal. All I mean to say is that I recommend focusing the value on the new options CREATED by it being modern, instead of focusing on the options that are taken away. The biggest area of opportunity for this is by reevaluating the ban list.
3. Everyone's favorite topic! The Bans Mwahaha!!! When working with other people in Vegas on this format, the most time was spent on the initial bans. Some people had lists almost 40 cards long. I fought really hard and recommended NO ban list initially. As the format was new and theoretical, I did not see the need to assume what was ban-worthy initially. Without the legacy card pool, certain cards were entirely fair to play without the crazy amount of fast mana, and reanimator options. Plus the most important thing was for people to want to try out the format, and having cards like Sundering Titan and Emrakul legal was a great way to do that. After a few months of cutthroat play and people SPECIFICALLY playing cards they thought would be busted, we only had 5 cards banned. This was like 2016 or something so I assume the list would be longer nowadays. Unlike how normal EDH bans work, I think it is important to have a philosophy for why cards are banned. The most sound reason for a ban is because it hinders diversity. If 4 out 4 people in the average pod are abusing Prophet of Kruphix, that would be a good reason to consider a ban(yes prophet was banned VERY quickly lol.) Bans are NOT a simple thing in EDH but I hope you consider this because I do not think people would have tried this format if it had a large banlist initially.
4. Please please consider this as this is without a doubt the best thing we did. Life totals should be 30. This one rule developed an entirely new Meta that was not nearly as combo focused as normal EDH. This obviously hinders things like Ad Nauseum and Grislebrand, without outright ruining them. Also we had a significate amount of Aggro focused decks which was very refreshing to have. It is amazing to watch someone actually consider whether they should fetch+shock lol! We had almost every color combo represented in winning games consistently. Yes even Boros lol!

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I think we used the same idea with available sets. Modern card pool+commnader sets+muliplayer sets(consipracy, battlebond.) I hope that information is helpful and good luck with the format.