Hardware requirements for SPICEd desktops

Hardware requirements for SPICEd desktops

[Lucio Crusca]

Hello,

I'm considering to build a new server and to use SPICE protocol to 
deploy all the Windows guests to the local network.
It's my understanding that:
1. I should create the guests on the server
2. I should use remote-viewer on a minimal desktop linux on the clients 
over SPICE protocol
3. I should enable QXL on the server
4. I can get clients USB ports and soundcards working in the guests

Now, assuming I've understood the above correctly, I haven't understood 
what are the hardware requirements server and client side:

1. Assuming I assign 4GB of RAM to each guest and that the network has 
20 running guests at any given time, should the server have at least 
80GB (20 by 4) of RAM or can I "oversell" a bit and bet on the fact that 
only few guests will actually use 4GB?
2. What's a reasonable amount of RAM to have installed client-side, for 
4GB-RAM guests?
3. Should the clients have a CPU that supports VT-x?
4. Is it possible to have QXL supported on the clients regardless of the 
physical video adapter installed?
5. And what about the soundcard support? Will any linux-supported 
soundcard do on the clients?