Skull prints with supports on it's back side.
Face prints flat on the printer bed without supports. Much easier to get good results vs the other designs.
Pieces should snap right into place. Use a drop of glue if needed.
Play with X-Y contour compensation if the pieces don't fit perfectly.
The first folder currently matches these models:
The second folder matches the original 10x model (reduced scale to 83.31%)
The author remixed this model.
Combined two halves, organized the files