Trying to sort out a reliable method for farming wooden chest skirmishes

Chest drops are pure RNG dice rolls. Nothing a player does can affect the type of chest that drops mid-match.

Although the drop rate tables for Skirmish chests have been removed with the recent UI update, they were known a long time ago (Credit: Tacet).

To the best of my knowledge, these rates are still in effect for Skirmish chests.