For anyone Googling this same question, I was able to solve this riddle!
I wanted CLICK ONLY in the headphone output. Took me forever to figure out (honestly disappointed that this wasn’t answered by Cymatic).
What I did was:
1. Update LP16 to latest firmware.
2. Create new Multitrack song, putting mix on tracks 1-2 and click on track 3.
3. In mixer window, set to “Multitrack Output, pre-fader “.
4. Pull faders 1-2 (song) down to -infinity. Export song to LP16.
5. In LP16 menu settings, set output to prefader.
6. Profit. Now headphone will only have click, while your mix still comes out of output 1-2 in back of LP16.