Hi Epihaius,
Yes, you’re absolutely right! Why use a task to orient the helper when I can orient the rings themselves? Truth be told, I was quite chuffed when I worked out how to use billboards to get the effect but got stuck on the last one. From memory the last axis didn’t work as expected and I couldn’t work out if it was my code or a bug in Panda. For consistency I added the helper node you found and kept the billboards. Thank you for your solution, I’ll attempt a patch on my end.
I haven’t noticed the culling problem you’ve described but I will take another look. I would also be interested in seeing your version if at all possible.
Awesome 
I hadn’t thought of that!
Most definitely. I want to use this kind of picking in my editor as using a ray will be too slow for complex scenes. I think I gave the idea away when I realised you would have to put a custom shader on every object which would defeat the purpose of having a wsywig editor. Is this not the case?