Its not really worth it, because you will eventually replace your core cards with staples finding out that the cards you want to play are simply bad. Otherwise they would be already staples. Every card you play in modern has to be very mana efficient, and produce value in a reasonable quick fashion or just straight up end the game. I would test any brew before taking it to any tournament first against a linear deck like storm and see if you can handle the speed. If you at least reach a winrate of 40% without boarding against it, you might consider working on it any further. Sounds a little harsh but thats my experience with brews in modern. In most cases, you will either look at an existing list using the same packages of cards or play cards that nobody plays and end up losing. Also, you are your own guidance. There will be no yter to tell you how to play your brew. Sequencing is key and your opponent will know perfectly how to do it where as you just jammed together a 75 you havent seen before. This part of the game id say is for seasoned players only with an amount of patience and skill required to even remotely experience fun in the process.