Thanks, almost missed that.
Grunter, look through the pics, rubber bands are a good cheap isolation solution. They do however not last very long. Over time they stretch and break. You have the right idea, just be a lot better with springs. Nobsound are cheap and highly effective. Townshend Pods are a lot better. Second to last picture shows mine on a bench, same thing is inside my Moabs and works great.
https://systems.audiogon.com/systems/8367
If you elect to go Nobsound I suggest hot glue individual springs under your crossover board. Experiment first on a bench to find how many and where, then hot glue in place. Will only need at most 4 per board. This will leave you with the Nobsound footers and enough springs to do another component or two.