I'm a bit deaf on my left ear so I always have the balance of my headphones a bit to the left, for this reason I've been avoiding the pan and stereo games because I don't know if this will give me a false perception of the stereo field. Should I turn the shift off when playing these games? Or use it how I'd use my headphones normally?
I would say how you do it normally would probably be better, since that's how you're used to hearing things in your headphones. As long as the center image sounds centered you shouldn't have a false perception of the stereo field.
I'd think you just want to play around with it, depends how well your brain adjusts to your hearing difference. If you psychologically compensate and learn to hear a center image as center, then leaving it is fine. If you really struggle to do so, the shift might be advantageous. Play around to see which way seems to make your results better, since the goal is practicing what you'd eventually want to replicate when mixing, and this could be a good way to discover which way makes more sense for future projects and help you get to know your own brain.
I have greater hearing loss on one side as well. It does throw you off at first, but after a time you start to get a feel for what really is. It's still an objective evaluation, and once you dial in what the sound is for each location, you start to get things right more often, even though it's not what someone else might hear. You can use the headphones however you like, just be consistent with it.
