Question about applying stone over metal face of fireplace with lathe.

[CTjohn]

Hello,

I'm almost at the point of building our raised hearth and applying stone to our fireplace and need some advice. I am pretty sure the way to extend the stonework onto the metal surface is to screw lathe to the durock and covers the metal, that much I think I understand. But the fireplace sits 1/8" to 3/16" proud of the durock in places. (The fold out mounting tabs wouldn't allow for a half inch recess on the framing, it kept them back further, I probably should have taken them out and bent them in a vise..woulda coulda..) Should I apply a skim coat to the durock to even it out and then screw lathe on? Or just screw the lathe onto the durock and kind of fold it around the face ever so slightly? Also, my taper tape the seams on the durock to sheetrock joints so i have to sand that off. See pics. Im wondering if I would be better off taking the Duroc off and shimming out the studs. The pics show the sides sheetrocked but we decided to wrap the stonework around the sides as well so Ill be cutting the sheetrock off up to mantle height and installing durock there as well. . What would you do? Thanks in advance!