John Isner

I know John Isner has been using the O3 White for a while now with great success. (He's beaten Henman and now Benjamin Becker in DC in his second ATP tourney!)

I assume that he's added weight to his racquet but with the O ports it's kinda hard to put lead tape on. Anyone have any information on his specs? Does Prince just customize the weight and balance for him?

Thanks.