The best way to farm geodes is to increase your Capacity and lower your Dig Strength as much as possible. That way, your scoops won't fill your pan as much, and you won't have to pan often to empty it ...

Nevertheless, spawning Santa is as random as obtaining auras in Sol's RNG, and you will have to put in the effort and time to reach the target. Here's all you need to know about Santa NPCs ...