This took a bit of time to get completed, though a significant portion of that was down to the fact that I wasn't really able to give a particularly good description or example of my facial structure to the artist aside from my own scribbles, which were (being extremely generous!) rather lacking in detail and consistency. The result though as you can see was well worth the wait and then some!
Short of actually getting Zel to materialise in this physical realm (tricky) and to stand still long enough to take a photograph (near impossible) of him, this is about the best facial reference you're likely to see. It really is pretty much a carbon copy of the image I have in my own head.
Suffice to say, this is going to be my own reference when I get around to actually putting together a proper reference sheet...though given my rate of scribble production, goodness only knows when that will happen.
Sadly the artist has never posted this work themselves as far as I'm aware so I can't link you to the original.