A couple of units per hour, no more, no less
Guessing that this is a casino that you will be returning to and do not want to be showing a lifetime win in their computer.
If your game shows that you average making $50 per hour, do not rathole more than $100 per hour and do it even if you are losing.
I say this because ratholing too much can be often be spotted and might piss off the pit resulting in their crediting you with every chip they can not account for.
I also say this because if you have a big win, they know you had a big win so you can not hide it all, just a small percentage. You make up for this when you have a losing session by making your loss just a little bigger in their eyes.
Take a chip or two on your restroom breaks, pocket a chip or two when a new player comes in with chips, do the same when someone colors up, a dealer change or when everyone is occupied with something else. In most places, do not pocket black. Most casinos track black and higher chips carefully while really ignoring green and lower, so you pocket green.
ihate17