“As a participant, you take your turns or make your contribution, as do the others, so that you are co-creating emergently, bit by bit; you can’t know what all the components are going to be – or exactly how everything will be positioned until it happens.”
The same goes for a large group intervention. You might have a structure and a plan for the process but to create a real engagement amongst the participants you have to let go and let people co-create.
Look at the overall picture and the direction you (the organisation) are heading and let those who are involved take care off the exact details.