I converted a Boba helmet to a Jango, actually I'm been trying. I followed the direction to the letter, using the exact same paint and the blue tape. I wait days before taping off, and it still comes off with the blue tape.
I'm doing light coats and waiting in between, scuffing it, the whole nine yards. I've already painted the thing 2 times. It looks like the paint doesn't want to stick to the Krylon metal finsh paint, even with scuffing.