On the cheek weld issue, I have been a rifle marksmanship instructor for years, and would never dream of instructing someone to go ahead and let something like that slide (unless physical injuries prevented it). A solid cheek weld goes to both stability and consistency. The idea is to get the neck muscles to be completely relaxed, which requires resting the head in the hollow of the cheek, and to make sure the head is in the same place on the stock every time for a consistent sight picture. Having the head resting on the chin or out in space requires some neck muscle to maintain, which causes the shooter to get tired more quickly, and introduces motion from tensed/tired muscles.
Is a poor cheek weld something that you can get away with and still do some pretty decent shooting? Sure, especially off a bench (benches are somewhat forgiving of a lot of bad shooting habits). But is it something that should be encouraged, or taught as "just as good as any other way?" Absolutely not. And to suggest that kind of advice to new shooters who might not know better on a forum like this would be doing them a disservice.
I seriously doubt you will ever see any sort of reputable shooting class or firearms instructor teaching students that cheek weld is no big deal, or is something that can be overlooked. Obviously it is one thing that can be dispensed with when you are shooting from a non-ideal position in combat or something, but cheek weld should be used any time you can possibly get it.
So I stand by my comment on it being the sign of an inexperienced marksman.
The fact that some Communist design bureau designed a gunsight to be used without a cheek weld is not in any way an endorsement of proper shooting form.
Yes, I am fully aware that some US military personnel use a mini red dot sight on top of their primary optic in this type of manner, but that is purely a last-ditch form of aiming for emergency close quarters shooting. People who know what they are doing would never mount their PRIMARY optic in that manner, if they could at all help it.