I've done a good number of these on the fly jobs - however, caveat - no experience with said gear - but if it were dumped in my lap...
Depending on what kind of band (assuming they are making some noise on stage) - I might run a little closer...near/on stage...
I would use the V3 as the A/D - seems like I would rather take a chance on the Eurorack Pres, rather than use the MT A/D...Although if this were a regular thing - you'd catch me trying both ways...
It might be wise to run the pads on your mics if you have any doubts about the Eurorack trimmers...
I have a similar quality Yamaha mixer - and with something like a AKG481 I have to use the on-mic -10db pad to control the mic effectively - even with the trimmers all the way down, the channels were peaking much harder than I like...(point is - some mixers trimmers dont go all the way down)
(Who knows - maybe thats the best argument for using the V3 as the mic pre)
See attached pic for one common matrix setup I use - this band has only vocals and drums in the mix. The Apex LD mics are attached to each guitar players mic stand just above the knees..
This track - has a little instrumental screwing around before the song - but a decent example...
http://www.archive.org/download/londonfile2006-11-22.matrix/londonfile2006-11-22t18_vbr.mp3Level wise - set each as if you were recording them independently...I don't really use the percentage thing for this approach...If anything - I've found myself running the board a little on the hot side...