Try using something like IOZONE, mount the drives UDP/v2, and let it rock.
Why do you suggest UDP/v2, and not UDP/v3?
IN all my tests, with FreeBSD clients, v3 has never beat v2, and since in my cases the nodes are on a private non-bridged/non-routed subnet, the utility of TCP vs UDP in this case seems lost.
TCP is not required for V3 - it works as well with V2 (only always more slowly through any combo of vendor's servers and clients I can muster).