Do what I did to improve grip.
Strip of rubber (cut from old inner tube) wound spirally round the grip, anchored at the end with plastic cable ties.
(Click on image for larger view)
Unless you are fussy about appearance, it makes for a very easy and effective (and extremely cheap) work-around.
Served me well for many years, and didn't seem to affect the warmth getting to my hand.
I needed mine, not because the grip was worn, but because my hand was getting weaker with far too many birthdays. No longer required when I got a Get 3, significantly lighter throttle.