For a start, I’m very grateful for the detailed replies, many many thanks!
Luckily the one advantage of our local supplier deal is we can have consultation on the Entrasys switches, and they are experts on the model. I am not under any illusion that i could configure such a switch for optimal performance myself, i always did intend to have them set it up for me based on our requirements.
Thanks very much for pointing out the non-necessity of the hardware RAID card. I can use that money and spend it on the extra cash needed for the 6 port Small Tree card. I knew you could do RAID-0 in Disk Utility in software, but i assumed a Hardware RAID card would handle it better and take pressure off the main processor. I imagine that’s true for RAID5 and all, but not necessary for RAID-0.
I am doing further testing on our current setup, and will post the results here. But so far you’ve given me a lot to work with. Again thanks very much.