That's perfect. I was hoping you'd come up with that on your own. A knot won't hold in a wire cable. Try this... ...First, slip a piece of shrink wrap over your cable (two or three inches), make a tight loop around the weight handle with the wire then wrap the tag end around the running line several times. Slide the shrink wrap down the line over the wraps and heat it up until it grips. That should hold the weight under normal conditions, but if it gets hung up, would slip before it drags your boat under.
Now, just get yourself a clothes pin for a release and you are all set.