Assembly sketch and in-context parts for a functional assembly

Hi all,

Firstly attached is what I have come up with so far,

I'm looking to create a top down assembly for a toolbox using a sketch to drive the features for various configurations. I am looking to drive the assembly by the number and size of drawers, or the number of draws and size of the frame.

From my attempt so far I'm struggling to achieve a good flexibility and it seems that I have to define all dimension myself rather than driving them from another.

Any ideas (even completely different to my attempt) are welcome

Thanks all!

SolidworksAssemblies