I make a ton of those daily, fusion was my go-to, but lately the fusion has been cracking on BH mandrels so I use my Universal Bead Release go figure! I find it makes the holes tons smoother and easier to clean. It's the test bottles but I use either one. I don't even have to soak, they slide right off but it holds while working.
How are you bending them though?! (edit-oh the ones welded to a regular mandrel, nevermind)
It all depends on your environment what release works for you!
Nice colors btw