If the weight was in the keel
rather than in the hull
would it reduce heel.
And the further away from the hull, the more effective it is. But this does not really work very well with a lifting keel as you will have different stability for different lift
positions. Furthermore, the weight spread over the whole hull will need significantly different (and less) hull strength, than suspending it from a keel.
It is all about levers - the longer the lever, the more effective the end result. In this case, the keel length is the lever.