How do you all manage temporary teams?

I have multiple clients whom I create Miro boards for where I facilitate experiences with them. 
These are temporary teams. I wouldn’t want to add licenses for these folks, nor would I want to give them day passes as we are working on a project together from 3 weeks to a full year.

We are using the boards with the general public, so I often have to lock access while I am working on the board - I would like to allow access for my temporary team while the boards are locked to the public, but again, full licenses for these folks nor day passes seem to fit the situation.

Additionally, I would like my collaborative clients to have team capabilities without full licensure or day passes.

How do you all manage these “relationships”? Do you just allow them as guest users and use passwords to lock boards to the public? Or do you pay for a full day pass every time they edit your shared boards?

Thanks in advance for any insight / best practices!