Honestly mate, I'd avoid any stereo setup live, and just run everything mono to one channel. Running a stereo FOH mix just doesn't work well in most venues, at least without a lot of extra work, and it carries the high risk that what the audience stage right and stage left are hearing can be quite different, and neither group may be able to enjoy the same mix that those stage center are listening to.
I love a stereo setup at home, when I'm able to stand right between my monitors and hear a proper effect; love ping pong delays that way. Same as listening to a great album on a good pair of headphones, the stereo effect really can be appreciated, but live....just doesn't work very well.
Given how many variables your already dealing with, I'd just set-up basic, good sounding, simple patches, run mono, and deliver that same thing to the right and left FOH speakers, as well as your on stage FRFR monitor speaker. Remember, "our" goal here is to get you one dialed in tone, that sounds good, both to you on stage playing, as well as by everyone in the audience, be they standing in front of the stage, or maybe over by the tables far stage left or right, back of venue etc, as well as having your bandmates also hear that tone accurately too.
Sounds like you do gigs in a variety of venues too, so your motto should really be "have tone, will travel", and the Axe delivers just that. Remember in the Metallica video, where they were saying how they love the Axe, because its the same tone, night after night, venue after venue. They just show up, plug in, and don't even have to think about tweaking the sound at the board, just running the mix totally flat. How cool and simple right ?
That (on a non-Metallica world tour scope) is that you need to aspire to think I. Having your tone dialed in as it comes out of the Axe. Not too muddy, not to harsh, cutting well with the band mix, and becoming a fixed variable. You guys just show up, plug everything in, and without adjusting anything on your tone, other than volume, deliver it to the FOH, and done. Adjust your keys, vocals, horns etc as need be, but keep your guitar tone as the benchmark in the mix.