The charm u need for this method is Unbreakable Strength(for shorter farm period)

Colosseum of fools is the place you are looking at.
You should do the Trial of the Conqueror, who gives you 2000 geo/clear
Trial of the Warrior is also good but gives you only 1k/clear

Nail Upgrades: Depends on skills i cleared it with only 1 upgrade
Vessel/Masks: Again Depends on skill, I cleared it with 0 vessels and 1 mask
Locations: City of Tears, Kingdoms Edge
How To Find it:

Credit to Relyea for the vid