Regarding Green Shards:
Total Encounters: 413
Relicanth: 23
Green Shards: 3
Deep Sea Scale: 1
Time: 3 hours, 6 minutes
Well, this is highly discouraging. It takes longer to obtain shards for one move than to train an entire Pokemon (EV, leveling to 50). And I still have to do this for 3 more moves. :(
Edit:
I also tried the Repel method, but after 8 Max Repel and no encounter it didn't seem very financially efficient.