You can definitely run 2 PSU's to power 1 machine. The biggie here is that you only hook up 1 PSU to 1 board, I think that's how it is actually shown on the Canaan site for 741 hook up.
If 1 PSU dies only the board it is attached to shuts down.
That looks nice! great to see you make use of the server PSUs which can be had pretty cheap on the secondary market
Are you running them on the same circuit in the home or splitting them up? Probably just 13-15amp load right?
You can run them on 1 circuit as long as the circuit is big enough, which all will be if you only have 1 unit.
for 110V you can have 1 741 on a 15 amp circuit, or 1 821. 1150w/110v= 10.45A , 1200W/110V= 10.9
If you are going to be running multiple machines I suggest going with 240v circuits.
I have been trying for months to get help setting up their new version of AMS. The instructions from their own github are incomplete and I have yet to receive a single answer in their official IRC support channel.
That sucks about the Canaan AMS, but you could look into awesome miner, you pay for it but I've heard good things. I myself don't have the problem of managing that large of an operation... mini mine, lol