There were few things I personally did to achieve that in the past:
• Eye for the Cassie prep groups, ideally 1-2 weathers before Blizzard weather sets in. Being in these pre-prepper groups yields you so much lights you’re usually guaranteed to overcap your kettles at least twice or thrice per session.
• A purely solo farm would be chaining or mass pulling mobs 2-3 levels above you. On bonus side, try to kill an undead/sprites on #20 or #30 chain to fish for 1 full bar of light bonus
(this bonus part is anecdotal from my own experience, take it as a grain of salt). Mind you, this is very mind-numbing even with full elemental gears.
You can hit me up if you see me loitering in-game. If I’m able to at the moment, I’ll give you a hand.
