Any hints on ODS design/Uniting Cubes?

Hello Experts,

1.

with 5 cubes and a plan to design a ODSes, what is the best approach to design ODSes? i.e. with the datasources, including R/3 and flat files, any recommendation for the best design?

In other words, knowing dimensions, theier characteristics and key figures for the fact table, how do you approach ODS designs;

2.

I also plan to use multiproviders to unite some of the cubes? With respect to the multiproviders, what are the determining factors to choose particular cubes to unite.