Record the Main input on odd track numbers and Aux input on even track numbers.
Allow routing of odd track to Main output an even tracks to Aux Out.
Alternately just support quadrophonic mode like stereo/mono … and perhaps cut 6x6 to 3x3.
Beyond the obvious use case (quadrophic loops), this is useful for having wet/dry loops (where the dry can reamped later) or support different output devices via with specific needs for cabsim, reverb, custom eq).
Lot
Additionally and related: the ability to treat the stereo input as two mono inputs on a per song basis would be really useful. I use one channel for guitar and one for vocals. It would be nice to be able to establish a guitar loop while singing a verse so that when I play back the loop on the solo, there are no vocals.
I have exactly the same need as you. In addition to it i run my voice through a voice processor for harmony. The voice processor need a guitar feed in order to correctly add the harmony. Would be great if it would be possible to assign the track record button to the left or right input. That would make it possible to use a single looper to perform as a one man band.