I've been using ‌ idea of SSP and love the concept.  Issue I'm having now:  Created Assembly that includes many sheet metal parts.  Most of the parts are an assembly with the SSP to drive the dimension of sheet metal part.  Many of them are lofted bends.  Some of the dimensions in the SSP are driven by equations.  What happens is when creating drawing using the flat pattern it randomly loses connection to equations and shows errors in feature tree.  Sometimes simply opening the part and closing and a rebuild will fix it.  What am I doing wrong?  

Also been a challenge, I have some sketches for etching that are on the flat pattern configuration.  To edit flat pattern I cannot be in assembly, but opening part outside of assembly I lose my driving feature the SSP!  Usually this is not a problem but seems to be quite fussy the sequence of how I open and save it in the flat pattern, otherwise I see red!