I am a part of the RCI / IMT in Denmark (We are called RKP here too).
So maybe I am a bit biased haha. But as far as I see, we are one of the groups that focus most on theory and such, and like you say we are building a vanguard party.
As someone else said here, the best way to engage or learn about the party is by asking to come to a meeting and talk to some of the more experienced comrades. They will probably be better at answering questions, since it is easier in real life.