What are your experiences with promoting companions as your vassal?

Basically. I am just planning to create a southern sea state as Aserai culture where I own all the port towns and Aserai towns in the south. But I don’t want any existing clans as my vassal for RP purposes. Instead I want to start promoting and creating new clans that I can name. And I want those companion clans to each own 1 castle as my security patrol forces.

But. Idk how it will turn out. Eventually with 15 small clans and me as owner of all towns. Idk how annoying it will be. Obviously with in game clan recruiting. It is too easy for me. And I want to have multiple generations run with this campaign. Thus I want to RP as recreating a new ruling class in the south with highly centralized state with provincial response forces (my castle companion clans).

So. Do any one of you guys have experience in companion clans? What are they like? Since I am already swimming in gold. I am planning to give each clan 1 million to start. With full garrison that I will be building it up.