I've never sprayed a tub down yet and my snakes have one piece sheds every time they shed.
I'm personally not a fan of spraying tubs, there's no need to jack the humidity up and have it fall just to jack it up over and over in a cycle of too high then too low of humidity.
Don't put too many holes in the tubs and if needed slide the water bowl back over the hot spot also works really well for shed period.