When a caseback has been secured with a caseback tool, does the tape (or other gummy ball) really provide enough torque to unscrew it?
I've tried several times on watches that have the "notched' caseback (many Seikos, rep Speedmaster, rep Planet Ocean) and found it took some "oomph" even when using a tool. I couldn't imagine budging them otherwise.
just ball up some duct tape with the sticky side out and you will have no prob unscrewing the back.