For the weekly tournament, I had an idea similar to it, and it would probably be an easier start.
A PUG group with a mandatory buy in when you PUG, be it keys or metal, and at the end of a week/month depending how many people played, the winnings get split down the top 3 or something. Instead of a PUG group it would just be a google form they fill out to sign up your team and players, then add someone to trade your buy in to, and over time maybe add a payed option.