@kevin. Two temp fixes for the lack of custom screens for now if and until A&H issue a firmware update with some goodies in ti.
So, I simply connect two screens/iPads/PCs ( 2 is the allowable connection quantity). Set each screen to a different window, sy Ch 1 to 8 and the other 9 to 16 or any mixup that suits.
OR
Option B is splash out on Mixing Station for CQ, for very little money (£6 approx in UK) and use that as one of your screen connections. It has a bit of a learning curve but you can have custom layouts AND virtual DCA to control groups and also that will include a mute button for that group. Once I have setup and soundchecked, I have a custom screen with iDCAs to control drum channels, backline instr, all vocals, group vocals (Mainly for off stage muting) and the interval music channel plus master. As I also play keys I dont want to be switchjng screens.
None the less, I add my vote for custom layouts and VCA/grouping etc.