As long as you don’t need overdub using flex is straightforward-ish to set up multiple loopers without predefined lengths and without worrying about tempo changes timestretching material. This process is made much easier if you use an external midi controller to map controls. It has been a while but for some reason i remember rec length had to be set to 64 instead of infinite but i don’t know why. 64 beats is pretty long especially if you set bpm to 30 (if you’re not using quantized recording the bpm can be whatever).
Dirty flex looping:
Set loop in playback setup to on, timestretch off. I have recorders set to quantize play and record to taste (I use Qplay 4, Qrec 4), but it can also be unquantized. When I press rec ab, rec cd, or rec src 3 it starts recording my loop on the beat (ONE2). Then I just hit the track sample pitch=0 button (note C6, see OT midi reference) and the rec ab, cd, or src 3 button at the same time to stop recording (quantized) and start playback (unquantized). The need to hit two buttons at the same time is why an external midi controller really helps. This doesn’t give me quantized playback start but it’s close enough for my needs and if I want to nudge it to be quantized I can use the onboard trig buttons in track keyboard mode, the track + play command combo, or drop a play trig on the sequencer.
Overdub is technically possible but very imperfect - need to record from src3 cue and setup feedback.
I had tons of start values, record, playback, length values for buffers set up on midi controllers and it worked pretty well. Essentially I was trying to contort an octatrack into MLR, and so when i discovered some of the max/norns applications here on lines I realized that these are purpose designed tools for what I was trying to get at. That said I still use my modular through OT rather than norns 90% of the time because it can do so many things simultaneously in a small package (fx, looping, sequencing).