SQ-6 As Stand Alone Monitor Mixer

I’ve got a regional multi-day festival coming up, and was wanting to use a SQ-6 mixer with an AB168 remote box as a dedicated monitor mixer for a two console set up. The band’s requirements dictate that I will have to run a variety of both in-ear and wedge mixes throughout the event. I was wanting to know if there’s an easy way to re-assign the Main Fader to control the volume on my cue wedges, while still leaving me the freedom of using the headphone output to monitor the in-ear mixes.