Setting up the Organisational structure in ARIS

I am about to start setting up my organisational structure in ARIS.

Initially, I will be using the organisational unit object, with position/job and person objects linked to it.

However, I also see the need of creating libraries of 'role' objects to indicate the types of role that position/job objects are composed of, and also a 'job type' library.  The difficulty I face is that my organisation has little standardisation of roles, job descriptions etc.

I would appreciate the advice from anyone who has developed an organisational structure and what issues and learnings you could share with me?

thanks