I have this PCB and I'm getting ready to order some missing parts for it.
@chongmagic Thanks for posting the inside shot, it clarified for me how to orient those photo-resistors.
Hard for me to tell from the picture, but did you use 5mm or 3mm for the opto-coupler LEDs? The build doc says 3mm but seems like plenty of space for 5mm to fit, and I'm wondering if there's any difference in using one or the other.