Ok, haven't played with the snapshot thing, but I'm sure you can make instances of the lwer level assembly with the "flexible" springs at different stages of compression (from free length to coil bind), then use those instances in an instance of an upper level assembly family table, getting you what I think Antonious is looking for.
When I get time today I'm going to try that out. I made a compression spring that has built in flexibility and it worked great in the mechanisms I used it in.