Transition strategy for Advanced Collections (R11.5.02)

We are in the process of testing Collections prior to implementation later this year. However we're not quite sure how to handle the transition period from dunning in AR to our strategies in Collections.

When we first run the Collections processes, delinquencies are identified and strategies assigned. However they all start with the first workitem, when in reality our collections processes for many customer accounts will have reached later stages. If they have already received a final demand, we don't want them to suddenly receive a first reminder email.

Do you have any advice, particularly from experience of other customers transitioning to Collections from AR dunnings?