Just made this for a christmas present with a picture, and it seems to be working fine.

The round holder is for a standard tea candle ( i used a LED tea candle as it wouldn't burn the litophane) :-)

These dimensions is MY OWN settings for my litophane picture, you might change it if you like :-)

x: 120mm (as the space is 120mm, do this at your own risk! :-) )
y:Up to you but 160,8mm has shown me the best result heightwise!
z: 2,4mm was mine and it worked fine!

Happy Printing! And happy holidays!