Things I'm learning as I go, and which I suppose experienced players know very well:
1. The term I heard is "input suppression". Essential for low area. To suppress a single, such as the mercury input of this puzzle, must have at least 2 grippers.
2. For low area, track seems another necessity. Put track in hexes that the material must visit, and move the arms out of the way of passing material.
3. A shuffle of material (to keep input suppressed) at an acute angle (60 degrees) doesn't work, the material will collide. Doesn't work for arms either, still collides. Must be 120 or 180 degrees.

If it comes up, something I will check is how close material or arms can be to the end of a very long stick as it is swung. Wonder if someone has put together a guide, and I just haven't yet learned of it.

And I have observed that in the videos, our host is using game enhancements. In particular, the ability to zoom out is really nice.