I am trying to add a few pieces of extruded hardware for a display case I am making.  The item width and heights will be based on the overall display case width and height.  I have tried adding the items as a hardware item, but that leads me to a static size.  I have tried adding the items as a "added" part, but then the part is extruded to match the specified material thickness and this doesn't work.  I looked over some posts regarding formula driven materials and tried it, but didn't get very far.  So for the experts out there, what is the best way to add these items?  I am specifically talking about CR Laurence sliding door tracks.

TIA