Ive done a bit of testing and this is what ive found

it is mainly based on your rank vs synth rank
everything else contributes too small of an effect to make a difference
add RNG and thats it.

once they rework things, stat points, recipe fixes, etc I will resume testing, but right now its pointless.
there are many ppl who want to do testing including myself, its not that no one cares, just right now its a waste of time till things are fixed

as far as moon phase/direction/time of day/element, i did many synths in a controlled expirements and the results were to small of a difference to really benefit, how you think you found a moon phase that give better hq, i would say that "its in your head" and is RNG, but thats my opinion based on my results, i could be wrong, but usually the numbers dont lie.