Here's a screenshot of what I would do (doesn't matter what note number you use — I just randomly chose mine). The top modline is just a normal toggle — the second and third work together to create an inverted toggle.
Map the top modline's note to the stop function and the second modline's note to the play function. This can be a little difficult in Live when you have multiple messages coming from a single key — it confuses Live's MIDI learn function. The best way would be to temporarily turn off the second modline, map to stop, turn the modline back on and turn off the first one, map to play, then turn the modline back on.
Seems to be working just fine alternating between stop and play for Live's looper.
Alternatively, since it seems you're in Hosted mode, you could use the Top and Bottom sources instead of Foot On — this will basically turn a single key into two separate keys, the top half and bottom half.
2, 3, 5, 13, 89, 233, 1597, 28657, 514229, 433494437, 2971215073