Steadman Harrison shows us a great option for using the Transformations deck with larger groups which requires fewer decks and potentially less time. He suggests laying out the cards before the session, clustered in the seven stages. Then, talk about the catalysts each person has experienced in their own development.
We laid out the cards in stages with the group ideas for what catalyst most naturally moved individuals or groups from one stage to the next. If you set it up like this rather than having individuals and small groups make sense of it on their own, it saves a LOT of time!