The standard length AK stock is the proper LOP. It has the same LOP as pretty much any other fixed stock combat rifle you come across. The NATO length is actually too long for natural shooting.
One thing Ive noticed when I see people complaining about the stock being to short is, they dont shoulder the rifle properly, and try to get a cheek weld on what most would call the "comb", on the rear portion of the AK's stock. The place you want the cheek weld, is on the narrow portion, just behind the top cover. You want your head down, and your nose to, or alongside the top cover. This will give you a natural and proper sight alignment when the rifle is shouldered.