I use 15lb balls on my 2 Scottys. once you try this you will never go back to a lighter ball. The Scottys are designed for up to a 20lb ball. There is no stress on the units at all. If you are have problems with stress on the mounting points, then it sounds like you need to re-enforce the mounting points with perhaps a metal plate. 15lb balls enable you to get to the bottom easier in the currents and are much more reliable when using the line counter. You owe it to yourself to give it a try. It makes Blackmouth fishing a whole lot easier also. Jack