Just giving this thread a nudge, due to my recent experiences with leather.
I just have one little bit of advice regarding leather.....switch to leather because you prefer the feel of leather, not because you want to add weight in the handle.
Ive seen a few threads where people add a leather grip to add weight.
I have been toying with various leather grips to try and get the right feel and have failed. It basically comes down to the fact that I just dont really get on with the feel of the leather. The difference it made to the HL balance was negiligible. With a racket as light as mine, it doesnt really need to be too head light. And I'm now of the mind that the manufacturer created its stock balance for the simple reason that it works best.
The unfortunate problem I had with leather was quite the opposite to the reason a lot of others prefer leather....I actually felt like I lost the feel and feedback I get from hitting deft drop shots and volleys, I just got a very muted feel. I also found that my grip was a lot less relaxed with the leather grip. The firm feel subconciously made me grip harder to hold firm (I always use an overgrip too).
Its a shame, because leather does look great, but having tried many alternatives, I am back to synth plus overgrip. Part of me thinks, why did I bother taking the original synth grip off in the first place, but I guess if I hadnt, I would never have known what worked and what didnt work.
Can't remember what my point was now....oh yes....use leather because you like the feel of leather, not as a way of adding weight.