Elements and the moon phase

Into crafting again at the moment; it's great fun!

But when is the best moon phase for skill ups? Some people swear it's New Moon, some people say Full Moon. I heard New Moon was "hardest" so was best for HQs, while Full Moon was "easiest" and best for success. However, since you can get skill-ups from a success or fail... is that even relevant?

Anyway, other people say they have best success on the corresponding day.

Reading a thread earlier I saw someone suggested it could depend on the association between the crystal and the moon. I'd never even seen that suggested before. But we do know that three elements are associated with light and three with darkness:

Light: Fire, Wind, Thunder
(Burn, Choke and Shock or Fusion → Fragmentation)

Dark: Earth, Water, Ice
(Rasp, Drown and Frost or Gravitation → Distortion)

So, if we associate Light with Full Moon and Dark with New Moon, you can see the link between the crystals.

It's also worth noting that fishing results are widely believed to be improved at both Full and New Moon, with a decrease at Half Moons.

As I said, not stating any facts here, I'd just never seen that hypothesis before. I like this hypothesis, though. It has a nice balance to it and I think SE loves that sort of Yin Yang thing.