Hi,
you need to have a look at SAP note 928729.
The attachment CUUC46C_to_NW740.zip contains the CUUC guide, which you need to use for the CUUC process onyour systems.
I would recommend to do a Sandbox conversion, as you probably need to meet downtime requirements.
For the Unicode part, please read SAP note 1322715.
Best regards,
Nils Buerckel