I also have RSI issues. I develop numbness and pain if I'm not careful with what I do. It can get pretty extreme, with the issues starting in the ring finger and spreading to the rest of the hand and then radiating into the lower arm and later the whole arm and to the shoulder. I can manage my problem very well and can be completely free of pain if I make sure to do some light strength training every day like push-ups or going to the gym, and a tiny bit of stretching for the hand and arms.
I never tried a vertical mouse long, just for an hour or so. I can't really see myself playing games with a vertical mouse.
The thing that I found out about mice is that the opposite of ergonomic is actually the best for my RSI problem. An ergonomically shaped mouse and using palm grip feels very comfortable to use at first, but my RSI issues will always come back when using a palm grip. Over time I found out that using a small mouse and finger tip grip does not feel comfortable to use for me, but I can stay completely free of pain long term. About what I mean with "small mouse", I currently use a Logitech G305 and my hand size is 19.5cm from palm to tip of the middle finger.
I also found out that using a sensitivity that's much lower than what's comfortable is the best for my RSI issues. I'm guessing what's happening there is because I'm forced to move the mouse around a lot, the work gets distributed over more of the arm and isn't just done in the hand or wrist.
Last edited by deepor; 07-07-2019 at 04:25 PM.