I'm new to the 'top down' design method, and have a question about how configurations are handled.  We produce products where there are several sizes produced - essentially scale versions of each other.  Currently, I am using a bottom up approach where each assembly, and parts has multiple configurations (one for each product size).  My drawings are tabulated with as many as 30 p/n's, that are linked to the design tables.

I can see how I can create an assembly sketch that drives my design, and how I can have multiple configurations in this assembly.  Additionally I can see how it is possible to create subassemblies that have multiple configurations.  But how do I link the two parametrically?  An example would be highly appreciated.