I think after the next passes it wont be that hard to tile, tileset extractor gives about 50 unique 16x16 tiles with a tolerance of 8 diverging pixels, probably much less if you tile at 8x8, perhaps even 8x16 (vertical rectangle tiles). It should drop a lot more if you decide to you remove some 8px offset and realign stuff after you do the detail and clean up:
Also, great stuff as always, you can feel it will be an awesome piece.
