just watched the cacophony tech tips volume 6 i think it was.
i used sylenth the same as you but with logic, i keep getting a click at the start of my midi notes though. ive got retrig on.
ivce had a play about changing the note lengths etc but nothing seems to be working.
any ideas what it is?
have you tried notching the attack up on the amp envelope?
have you a sidechain compressor on?