Sony PUA-9 What's the mass of heavy counterweight?

I have a Sony PUA-9 but only the standard counterweight. It struggles to balance most of my cartridges, so I was curious if anyone owns the heavier weight. If so, how much does it weigh? I plan on having one fabricated. I guess I could just have something made that is a bit heavier than the one I have, but I figured I might as well go with the stock weight so I can balance the full range from 10.5 - 33g.

Thanks in advance for any help!