I also have 2 greys, one of whom is 2 years old, and the other has just turned 1. My eldest did have a spell where she would scream for quite long spells at a time. I completely ignored her, and as soon as she stopped for a minute or 2 I would go in to the room and talk to her. The only thing you can do is ignore them, hard as this may seem. By going near them to cover them you are inadvertently giving them attention.
And I would never ever squirt your grey to stop them doing something. As you have already discovered, you can now no longer bathe them with a spray bottle because they see this as punishment.