Our praise band has different singers and instrumentalists each week. Each week at practice they have to re-setup their mixes (using the SQ4U app). Is there a way to save and recall a single mix in an aux channel?
You would have to save a specific scene for that group of musicians. When you go to save the scene, you can isolate which channels you want to specifically want to save to that scene (i.e. Dave the drummer hits harder than John the drummer, so you save a scene as “Dave on drums” and a different one for “John on Drums”)
The scene should save the Aux Mixes as well, and therefore solve your problem.
To elaborate further, for your FOH scenes, you normally want to safe or filter the IEM mixes so they don’t change when you’re changing your scenes. To save and recall IEM mixes, you would do the opppsite: create a scene(s) and safe everything BUT the IEM mixes. Off hand, I think safing specific mixes is handled in the Global Safes, so you’d go in there, unsafe your IEM mixes, recall IEM scenes, then re-safe the mixes. You may be need to use a combination of global safes and recall filters to minimize the hassle.