Hoo hah.......... No duct tape ! Sticks too hard.
Any kind of masking tape works. And width.
BTW, if you look closely at the pictures they show the only problem you have with the technique. If you pull too hard, your fingernails will suddenly elongate. And become polished. And clean. And your freckles will all disappear. Some things in this hobby you really got to be careful of.
