I have an XR18 and I want a convenient way to 'Pink Noise' a room to get a reasonably flat response. I'm using AudioTools on an iPad which does an RTA using the iPad's mic, together with an android phone running Xair Edit to EQ the main LR output.
It works OK to get a rough EQ balance, which is obviously a compromise depending on how varied the room is, and is a good starting point.
Using two devices is a draw back and matching the GE with RTA display takes time.
Have you thought of adding a similar function to the AudioTools RTA into Mixing Station and having it as an overlay option?
In my opinion it doesn't need to be super accurate. I don't trust my current arrangement much below 100Hz and much above 10kHz either.
I have just discovered Mixing Station and am trying out the android version.
Mixer Model: XR18
App Version: either iOS or Android