My indicators made By Bill Simms uses two 1/4" nuts. On a very windy day or when it rains I add a third. Rain will add enought weight that the cups go to the bottom and stay there without adding the extra counterweight.
I use a wire rope connector, basically a u bolt with a crosspiece and 2 nuts. I move the connector up or down the shaft to achieve the balance I want. I think I paid $.79 for it, maybe not very eloquent but extremely effective.
There is not a "Weight" Rule of thumb! Every indicator is different - if that makes sense?
If you are planning to buid your own?? than I could give you some Target Points to use??
(I Have Built a lot!)
Go to the Wind is Not Your Friend. I have put a lot of info there. Once you have a good understanding of what I have written come back here with any questions & I will try to help.