Bob,
Tommy Granger uses this on his Jav. and really likes it. He found the stock ball component a little heavy and made some new ones using synthetic line threaded through a small diameter hose for abrasion resistance with the ball at the end.
He added a disk half way up the component made of CF and foam. You grab this with two fingers to positively locate the ball into the slot in your harness. Worked well all last season and I'm sure as a fully fledged A Cat junkie you want to keep weight to a minimum.
If you ask nicely he might make you a pair.
Chris.