Andy

I've come across this many times.

Golfers elbow as it's known is a popular injury in badminton and overgripping in terms of tension is one cause. My recommendation here would be to use the heat shrink sleeve which will thicken up the grip and maintain the natural lines you need to appreciate which grip you are performing.

The other thing to remember is that your racket should be held in your fingers and not in the palm of your hand. So be careful that you do not build the grip too much otherwise it is sitting in the wrong place.

The heat shrink plus a thick grip (Karakal make some good thick -ribbed grips) may be perfect for you bearing in mind you do have big hands. These ribbed grips may help more for you. The other point could be whether you sweat very much. This sometimes leads to overgripping. If so, a resin powder will make your grip sticky but may just be the thing to help you ease off.

There is a thought that if you have over-corrected the overhead problems you previously had, there could be some referred pain from your neck/shoulders which is not helping either.

Overall, you should hold your racket with the same tension you would a pen and only squeeze at impact. Spend some time focussing on your grip rather than your game as the more times you catch yourself over-gripping, the more you will correct.

Andy, if you want to talk this through, then you know how to contact me and feel free to do so.

Paul