Here's for the lazy people, now you don't have to illegally rip my opacity mask from my derivation (not appreciated btw):

I suggest using a 256(W)x512(L) texture and opacity map. This mesh is automatically mirrored so it's perfect for horns, ears, or anything else you want to duplicate on either side of the head. I have included a second material ("01" within the editor) that sits directly behind the first material; You can use this material to create glow or similar effects very easily.

If you have any questions or confusion please feel free to send me a private message. I'm happy to provide more detailed instructions to new(er)/less confident creators.