I have been lucky enough to upgrade to a more powerful Mac. Can someone please advise me on the best settings for Kontakt 2, re. latency, buffer size, etc.?

my specs: PowerMac G5 Quad (4 x 2.5 GHz processor, 4GB RAM) 2 x 250gig hard drives.

Using: M-Audio Firewire Project Mix I/O as audio card.
Mostly with Nuendo, Cubase SX and ProTools M-Powered.
Also GPO and East West Gold.

Many thanks in advance to anyone taking the trouble to reply ....