JVM settings for J2EE server & dispatcher (HP-UX 64 bit itanium)

hello gurus

i wanted to know more about

1: JVM related settings for J2EE server and dispatcher in HP-UX, 64 Bit environment. Machines are Itanium.

2: How many server and dispatcher nodes one should configure on one physical box, with what basic memory parameters and what should be physical memory.

thanks in advance

regards

shoeb