.STL File Troubleshoot

Aloha,


I just receive my Cetus 3D Printer & I unbox it in this Video:

https://youtu.be/_tYebqjKg8c


When I load my .STL File, the Slice processing took a long time.


Does Slice processing take longer if I select "Fine" print?


Or is this a result of a .STL File with defects?


I try to print a Human Head, but in the Mouth..., is Tongue & Teeth (i.e. Open Space); so perhaps I need to close the Mouth?


I then load a File from online & it loaded very fast.


It is printing now.


Is it better to print 1/2 a Head (Symmetrical) & then glue the two pieces together?


The Nose, Chin & Ears overhang & will need a support otherwise.


Anyways, any feedback will be appreciated.


Thank you.


Antonio