I had an outing with 2 grams of lead at 3 and 9. I already have a leather grip on there, so we're still talking a pretty headlight balance.
Does it make a difference? Yes, but depending what you're after, it might not be worth it. The biggest improvement was that it gave visibly more zip to the flat serve. My 1hbh was slightly more stable, but not by huge amounts. The more I'm conscious of it, the more I think this is linked to the large head size. My forehand, which was the shining light of this stick, went down a notch.
I've rather ruined myself by playing with the TGK's again. The Prince just feels so tinny in comparison. I'm mentally fragile at the best of times, and I don't think I'll recover from this: I'm probably done with them. More alarming is that I'm starting to think about how I'd hit a backhand with a 93 sqin or below head, when I'm really not good enough to wield such a bat...
My String Journey: http://tt.tennis-warehouse.com/showthread.php?t=362403