I’m currently in a two piece project where I run the elekctronics and my friend plays guitar.
When we tried to use the OT as a more traditional style looper, it was a miserable failure. The lack of an undo was the biggest downfall, and it was immediately glaring and painful. Especially in a live setting it was pretty unacceptable.
So what we did instead was set up one side of the OT to be flex machines that function as a four layer looper, meaning that r1-r4 would record various layers of the loop we wanted. We were limited to only four layers, however the use of the sequencer, plus a “ghetto undo” (just delete the last recording since they are different files for each layer) and different effects “per layer” made it a lot better.
However, in our current set up, I loop the guitar while he plays it. The OT is an instrument in its own right and I would personally find it difficult to manipulate both a guitar and OT in real time.