I'm currently trying to put together a set of live loopy type stuff. My setup is guitar and vocals, and a laptop with an audio interface running Mainstage. Both the guitar and vocals go through the audio interface to be looped in Mainstage. I also have a few backing tracks set up by region markers. I use a MIDI foot controller to control the loops and trigger changes in the backing track.

It works reliably (well, it will with more tweaking) but I'm a bit concerned how to set this up in a venue. The audio interface has 4 mono line outs (as well as a mostly useless SPDIF out) and a monitoring out which dumps out all the audio. I can route to these 4 outs individually but really that isn't enough; there are a few tracks where I have more than 4. However I figure I can group them: put all vox on one out, all guitars on another, bassy sounds on a thirds, drums on the last. Would this work?

Also: I turn up at a venue and present these 4 line outs; what would a sound guy think of that? I've been told that I should possibly get hold of a cheap line mixer and have a single connection to the PA. But I'm already trying to sing and play guitar and control a looper with my feet. Is that overambitious? I'm also considering mixing using the volume controls within the software, but given that I have a lot of reverb and delay on the vox and guitar I would be concerned about getting horrible clipping if I messed up a bit.

Any thoughts/advice?