GGBB- No LED. depending on the status of the two fixed switches, the output signal will be
Mom off: input, mom on: loop.
Mom off: mute, mom on: loop
Mom off: loop, mom on: input
Mom off: mute, mom on: input
I think of each of these as a mode in which you would do one song.
This is more than what the OP is looking for, I just started thinking "I wonder if I could add a stutter switch.."
It's the only way to do this with these few resources. If you use a latching 4pst instead of a 3pst you could add LED status there, and you could add a pole to the other latching switch for an LED as well. But there's a lot of combinations here that you would still need to decode. If you look at the truth table in the other thread, you'll see what these LED s would indicate, and it would be only slightly helpful.
The latching 3p2t could be a toggle. A large visible one if you like. Since there is a momentary switch here, I don't see the latching switch as much of a timely stomp in the middle of a song - more of a more switch, defining the action of the momentary. Like a pot, you set it for that song beforehand, and then rely on the one stomp during the song. The LED would be great, and you could do it, but even if all the switches had one, I feel I would still need to listen to see where I'm at. Or tape the truth table to the back of the guitar, next to the lyrics. I plan to just learn how to do it. My song will be played in input mode with a momentary loop to kick in, or it will be a stutter switch with the momentary kicking in the input. Or the loop. Or I will play the song with all the wacky sounds in the loop and step on the momentary to kick in a brief clean part.
I guess I got used to my MXR dist +, with no LED.
As for the momentary having an LED, that seems kind of unnecessary, but I think you mean the other switches.
I do plan to make the momentary a relay for quieter and lighter touch switching, but I personally would find this very useful without relays. All possible combinations of Mute, Input, and Loop are there, except those that would offer a momentary mute, which I don't have a need for in designing a looper. Also, one condition - a fairly unusual one where you are playing through the full loop and want to momentarily kick in a simpler sound - would have the straight input sound connected to both output and loop input. My pedals are designed properly enough that this isn't a problem, but I must divulge this weak spot in the design. But improvements in the performance of this looper would require more switch poles and even another switch. Then the truth table goes to 16 options and the LEDS aren't going to help me with that.
{edit: I just wired and tested it and it works. Until now I was only asking people to look at the wiring and double check the truth table}