I like to let things dry pretty much a good day or so before lifting.....
Actually I've tried lifting the Fluid both a few hrs after and a whole week after...both worked just fine..
*** if for some reason you can't Lift certain sections of the masked area because the paint is too hard, then just use an Exacto to chip the paint, THEN continue lifting with the Rubber Cement Pick up on that area. Will come right up***Works great.

Hope that helps..