If you did infact shoot 720p24N then it is the DVCPro HD 720p24 Easy Setup that you want. That shouldn't require any kind of rendering at all. After applying the easy setup, create a new sequence and double check that it is infact setup correctly.
I would also consider trying the DVCPro HD 720p60 Easy Setup as well. See if that works for you. If it does then you should in 720p24 not 720p24N.