Cooperative models are enjoying something of a surge in interest. Your starting point should probably be to study the "Statement on the Co-operative Identity," and decide whether this fits what you are trying to achieve.
Then play devil's advocate, and ask the question, "am I really just describing a partnership?" -- which is less exciting and more straightforward.
(Looking at your linked question, I think that may be exactly what you're describing. For instance, if you're already thinking that a significant proportion of the team may not be eligible for a share on account of their role, that sounds like a partnership, not a coop, even a worker coop, to me.)
And if after all that you want to go ahead, I would make contact directly with either a national representative body (likely to be an ICA member) or a functioning Coop. You're likely to find all kinds of practical support, and access to appropriate model charters etc.
In the UK, The Co-Operative does an amazing job helping new Coops to get started, giving free advice and often helping access free expert consultancy.