It is a really simple job to adapt your Spomb to float.
Undo the holding metal pin, and push it back through the hole. I had some floating foam, which I trimmed to size, and push that onto the locking spring pin, then force the pin back through the original hole.
You now have a floating spomb which won't wobble on the cast.
An added benefit is you fill up the loading bay, and stop overload preventing it from shutting or opening in flight.