Cheek weld with the fixed stock and the collapsable stock fully opened are just fine, however the length of pull was too long for me. I am 6' and the LOP made it unnatural.
The collapsable stock shortened down to midway is PERFECT for cheek weld using optics, but is too high using iron sights for me.
The mount in the pix is this one:
http://www.mountsplus.com/thestore/prods/AIM-12243.html