@bunyip The fish (let’s call them levers, because there was a time when they were going to be birds…) sit on an aluminium angle. I’ve used a 3mm 25x25 - The force on it depends on where the balance point is so it needs to have a bit of robustness.- if for whatever reason you want to reduce the mechanical advantage and move the line towards the tail, you will have quite a lot of lateral force trying to topple it.
Note that I’ve adjusted the amount of cantilever by design, so the lines are pretty much vertical.
The levers just sit there, allow plenty of clearance for them, if someone gets over-exuberant with the line they’ll end up. toppling over, so a stopper on the line or a wire tie down onto the angle to stop them lifting would be smart. We haven’t needed either in normal use, but then the grandchildren haven’t visited yet either.
In my case all the balance points are different because I wanted them to stick out different differences. The small fish (Nemo) came about because I was using left over verandah floor timber and ran out.
Hope this makes it clearer, please say so if not _