Hey Ian. I ran a Test N Tune at Willowbank a couple of weeks ago on the ZXR. There was a guy racing a Busa who was having the same clutch chatter thingy you describe. One of the Old Skool racers advised him to launch at a lower rpm as the Busa has enough torque to pull out. First time he tried he droppped his time by 4/10's and did his PB.
Just a thought mate - might be worth a try.
Cheers