EXS 24 Logic Sampler Users Group

Hi everyone, I am new to this group. I am setting up a new 
system running Logic with the EXS24. I would like to know how 
many instances of the sampler I could have open at once. 16 to 
24 would be nice. I ask this because I wil be using high band 
width symphonic samples.
Also do you think I can get away with using a powerbook G4 with 
a 1gig processor.
Thanks so much for your help.

Moses