I agree with Bob here. AFP will probably NOT provide a “satified user experience”.
You say you’re using 4 X-serves as clients to feed 45 AFP seats. That’s 11.5 users per X-serve… which is in my opinion, pushing the limits. You don’t say what kind of work is being done by your clients, but what guarantees do you have that any of the AFP clients won’t start pulling major bandwidth (multicam, multi images, stills, etc). This is the stuff that will quickly bring your AFP users to a halt.
This is both a “delivery bandwidth” issue and a Raid bandwidth issue. It also depends on what your clients are actually doing. HD? SD? How many streams each? What is an acceptable level of performance for those clients.
AFP works great for certain specific situations. Yours doesn’t sound like one of them. Sorry.
Mark
PS. If you said you’re willing to work at “Off-line RT” resolution, then maybe, just maybe it would work.