I can vouch that this rack does work. The guy manufacturing right now happened to move next door to me and I worked with him on some of previous issues and he corrected them and nkw the rack works great.
Even got him to make a 10 ball rack that works awesome
These probably work great with perfect balls on a perfect surface, but I think you need the dexterity of your hands on real imperfect balls to push them together on a real imperfect surface.