Falken76 did a fantastic job of modelling the Witch King of Angmar's helm.
I've merely scaled his designs 14x so they (just) fit inside a relatively standard 15 x 15 x 15 cm build plate.
I've also uploaded an STL called "All in one" which has all of the separate helm pieces all orientated, scaled and ready to print on one build plate.
0.2mm layers and standard superglue should work fine. From memory, no support was needed. Add a healthy brim to keep the model nice and stable.