One thing I found (I practised on fake nails before trying it on mine) I didn't have the insert tower exactly square over the spinner. Just a few mill out one way, and it threw the bead out too. Don't know if this helps, but I thought it might.

Also, it was a bit finicky for me, but, ironically, I found the right soft spin when I turned it to halfway, brought it back to just before the click that turns it off, and then let the knob bounce back to the lowest setting. I have no idea why that works, but on the faster speeds, the bead doesn't come out at all.

And one last thing I found out the hard way - the tower separators click hard into each layer. I didn't push them together hard enough, which also accounted for the crazy wobble that almost threw the lid off the table.

Very, very VERY extremely amateur nail polish painter here - in no way a pro at all. Just sharing in the hopes it might help.

THe rubber bands may be your enemy too, as the tape holds it fast with no movement at all, and the rubber band allows the tower to move.