Theory, practice, theory. I have been in discussion with a couple of trainers and it seems that the normal way is to have an intensive training on Ruy Lopez in classes before you use it in Tournaments. But can you really use it if it hasnt been tested in battle?
I view things slightly differently. I consider the Ruy Lopez as a must know theory for anyone who wants to go further in chess. This idea was drummed into me by GM Ziaur and GM Wen Yang (in Singapore). They told us that you cannot avoid main lines if you want to be a strong player.
However main lines is tough work and the theory is ever evolving. Nonetheless learning it will increase your chess understanding. So the purpose of starting with Ruy Lopez is not that you will necessarily use it as part of your repertoire. Instead think of it as increasing your overall understanding of the game of chess.
This is the same method I use with Mark. Polish your main weapons but on the side, learn mainline systems and eventually your understanding will increase and maybe in the end there are no lines afterall. But this only happens when you know enough lines until they merge into a whole.
We are still working out the format and will keep you posted. You do not have to be a Ruy Lopez expert to play at our tournament but I do suggest that you start reading up now if you intend to play.
Start with some theory, play as many tough games as you can with strong players and you will see that at the next reading the theory will come more alive. And then we'll do it again.
All my best in your chess journey.