Hi Ken,
Please refer to the documentation of Interface IF_RSLPO_BADI_PARTITIONING. Method GET_T_PART_PROP is used for specifying a Data Class for each partition. Refering to the Layered, Scalable Architecture, it could make sense to use different table spaces for storing data according to layer and domain.
This method was introduced in EhP1 for SAP BW release 7.3 and is optional in my opinion. I have upgraded an SAP BW 7.30 implementation to 7.31 without using this method. In this case you only have to implement the method with a comment, no real coding is required.
Last but not least, please have a look at my Pattern-based Partitioning concept. You can access the blog series via Pattern-based Partitioning using the SPO BAdI - Part 1: Introduction.
Please let me know if I can help you with anything else.
Best regards,
Sander