What size cage? If a 16 you will most likely see some over spray since the spray is wide. In an 18 I've had no issues. Just make sure you position it so water isn't bouncing off perches and leaves out off you cage.
My mist sessions are 2 minutes a piece, the water is on the cage floor and not blasting through the mesh. A very tiny bit will make it through the front of cage where I have mine pointed, but you can only see it under bright light.