Really? How do you get around the wordclock issue? There was a thread about this in the A&H forum I believe.
Edited to add link: http://community.allen-heath.com/forums/topic/monitor-output-ar2412
Interesting. We were just interested in if it would work or not so we go plugged the monitor console (Qu16) in to the mon out and set the inputs to dsnake. Played some cd track through it and worked fine, there were no funky noises or anything like that which I was expecting.
We didn't play around with it for the full gig, but there was nothing that happened that would suggest you couldn't do a split this way
To be honest I was surprised when it was working fine!