doubts about avaya & vlan voice diagram

[fffrrr]

I wanna create a VLAN for Voice on Baseline 2948, and I wanna configure QoS on it but is my first avaya PBX and 3Com switch configuration. I dont understand completely, because VoIP is not my area but I have to configure this part of the network.

My doubts are:

. If the PBX is in a different network segment (192.1.10.0 /24) and my ip phones are in another (192.1.11.0 /24) Can I create a separate VLAN Voice, one for each segment? I mean can I create a two voice VLAN on one switch (3com 2948)?

I don't know if exist space in the 192.1.10.0 /24 subnet for the IP phones. But, for example, if doesn't have more space in this subnet (I mean, from .11.35 to .11.254 are in use) what can I do? What happen if the others subnets doesn't have the enought space for PBX, IP phones and the rest of voice configuration? What is the posible solution to this scheme?

Other ones:
. Is posible create and configure a VLAN voice on the avaya PoE switch?
. It is correct, based on the next figure, create a VLAN voice if the PC is on one subnet and my ip phone in other? How I can built this kind of scheme?
. What is the recommended parameters to my ip phones, I mean, priority, CoS to queue, aging, bandwidth?

Thanks...