I've completed all the printing and most of the wiring for the 757/767 throttle quadrant, and must congratulate you once again on a superb design!
I do need some clarity on how you have wired the LED's for the annunciators. From your Build Video in which you bend and solder pairs of leads together, I surmise that you connected each pair of LED's in parallel to a single Arduino pin, as this wiring diagram from your 737 overhead would also seem to attest:
Is this correct?
If in parallel, are you using any resistor(s) in series with each LED? And would it be necessary to use an external 5V power supply in this case?
Alternatively, could one connect pairs of LED's in series to a single Arduino pin, as has been suggested elsewhere? If in series, is there a need to also connect a resistor in series as well, and if so, what resistance value would you recommend?