How can I make my K90 from a 4 1/2 to a 4 3/8 while maintaining a leather grip?
That could be a good idea.If you have still got the original Wilson leather grip on your K90,you might want to order a Tennis Warehouse leather grip and replace it with that one.
The Wilson leather,to my knowledge, is 1,8mm thick, whereas the TW leather can be purchased in 1,3mm.
What other option do you have? Apply and have a hit with it, you could also use thinner overgrips (assuming you use them.)That could be a good idea.
If I played with it enough, would it compress into 4 3/8 size?