The deck has had three lead weights inserted. These were made from thin wall chrome tubing filled with molten Lead. I had these lying around from my sea fishing days. I just cut a length of tube matching the weight required and dropped this into a bored hole partially filled with body filler, when the weight was pressed in the filler oozed up and out of the holes and was then levelled with a palette knife. So the weights are completely encased and bonded to the plywood. The balance is not perfect but much better than before, each foot sees nearly 3 Kg and the max variation is within 6% of this load and most importantly if you measure the gap between the foot and the base they all measure the same.