Light Elementals.

Besides Ru'aun Gardens, what is the best place to farm Light clusters? I believe the only region is Qufim Island (B. Dominion, D. Tower, and Qufim)...Where do you think the best is?

Qufim isle has the most spawn points and fastest respawn in my experience.

I rarely see light weather in qufim though :x It sucks because of that.

I have found them in Upper Delfkutt tower before but normally there is lightning there alot.

Gardening would be your best option on this

Well you can be killing Gigas for gil when you farm the light clusters I do that sometimes when I am board and don't want to collect lot's of items

How about Qufim on Lightsdays even if the weather doesn't call for it?

The only steady way to get light clusters is Ru'Aun Gardens. Light weather is very rare and never lasts long in Qufim/Delkfutt's/Behemoth's.

Gardening can take like 3 weeks to get 1-3 clusters.

If you are breaking the clusters down to crystals for synthing you could try farming Cardians, Golems, Magic Pots or Tonberries which all drop light crystals.