Please excuse the lousy audio when I am talking. It’s a combination of my voice and not actually practicing this before I did it or doing any sort of sound check!
I have various tracks in 5 track increments in the loop pedal preset to specific tempos that correspond to the track number. So loop pedal track 120 is 120 bpm, 125 is 125 bpm etc and I preset them to fade when I hit the stop button.
So to select a specific tempo for a ‘live’ recording I just have to pull up that track number which I can do using the three button foot switch connected to the pedal, so no bending down to change stuff for me! When I hit the loop pedal it gives me a 4 beat lead in (if the track is set to 4 beats per bar and most are), so a one bar lead in and then it automatically starts recording until I hit the loop pedal again which sets the loop duration. The pedal then just keeps playing that loop.
Normally, once I have a loop down and as soon as I have changed the keytar patch and maybe effects pedal setting, I would start playing the next overdub partway through the loop so that I am not standing there doing nothing while I wait for a complete loop to end before starting an overdub. It does take some practice though to start part way through a verse sometimes. Well, it does for me anyway!
After that I can just hit the loop pedal to overdub whatever I want. I was also changing settings on the effects pedal to vary the sounds of some of the keytar patches I was using while I was playing this.
It's a Busker's Life For Me 