I concur with Richard anything you do needs to be grounded in the work. When we run the discovery session I do it spontaneously and without seeing any formal position descriptions and structural diagrams. The times we have used the existing structure and drawn out some starting circles I have found 2-3 meetings in its still all a bit fake and usually a project gets kicked of to discover the work anyway and make changes. So when we have started from a clean slate and focused on the work its been a much smoother start almost like a new beginning that has allowed people to show up in their roles focusing on the work and not the old habits and politics.
I just completed a circle that I felt was hard for clustering the work but the feedback I got was that what we produced was absolutely amazing for the first time the team had a clear view of the work happening in the area and in the words of the to be appointed Lead Link and amazing tool they can show their clients. They will be kicking off next Friday and they are much more comfortable with the process now its been show to be about the work.
So my advice focus on the work that is being done now not what you think should be done or what you believe others think you should do and you will have a great place to start. And as Karilen says there is probably at least 2 circles their but don't force it if it doesn't come naturally I am currently running a circle with 32 people in it and yes it is way too big and there is at least 3 circles in their but they where use to being that size as a department and the meetings currently run well because we have uncovered the work. The meetings do work and everyone can see it coming in terms of some sub circles and more structures but the change will happen grounded in tensions rather than in our belief of the ideal situation. This is an extreme case of course I call this circle the orphan circle because it was the department that took in everything that didn't seem to fit anywhere else but one of the exiting things about not overly structuring the beginning is we are now seeing as we bring on other circles where the orphans really belong at it will be less painful to move them as there is not a complicated circle structure at the moment the can sometimes hide them in layers. I hope that adds value I can ramble on sometimes