Phased implementation approach: Dunning -> Strategies

We would like to implement Advanced collections along with our implementation of R12.  As a result we would like to use a phased implementation approach with Adv. Collections.  1st phase we would be using out of the box scoring and a Dunning letter collections process. 

What are the risks or limitations of this approach.  Example; will we be able to convert from a dunning to a collections strategy approach easily?  Will we be able to implement customer segments with the strategies after the fact.  Any additional information or insight would be appreciated.