Gives a nice clean look to something with a similar thickness.  

The Wall Mounts have a flat surface on them, ( I included a photo with the surface colored green ), that you can use to set a level across  to get them nice and straight before sliding on the Brackets.

The height of the head of the screw I used was 2mm.  The width of the head of the screw I used was 7.5mm.  The model was designed around these since I already had them.  There is also a small cut out on the back of it to help allow for a small drywall anchor to sit more flush, ( I did not test this, I didn't need one as it turned out, lol ).

This slot thickness for what it can accept it 6.2mm, ( this is also depending on the support you may use, printing orientation, your printers accuracy, etc, but that is what the model is for, as seen in the photo again ).

Is something very specific for me, but maybe someone else can use it :D