OK it's a new year, so time to make changes. I give in. When the majority says 2+2=5, it must be 5.
1) The MR helmet is the correct screen size, as Barry said "The CloneTroopers seen throughout Episode III, we're all scaled at different heights" so one of those sizes, even if by accident must equal the MR size. I would even say the slight upsizing of the LFL downsizing (still downsized) while DIFFERENT than the "screen accurate" CGI files, still fits the dramatic license definition of multiple scales used within the film.
2) The MR helmet is perfectly scaled to Clone Trooper armor, not consistent with helmet to armor ratio in LFL concept art basis of the painting, but on this one, again, dramatic license can be taken. I even met a couple of clone troopers of rather thin frame at C3 that it probably would look good, complimentary. There ARE smaller helmets that ARE correctly scaled, like the DXFR RC bucket. Great helmet, correct relative scale, so it has nothing to do with it just needs to be bigger.
3) The MR helmet meets the definition of helmet, well it does fit me despite insults, so it must be a helmet.
4) The StarWarsShop advertisement more than half a year before delivery, despite being correct, must be wrong. Of course the movie with the accurate depiction was out for 3/4 a year before delivery too. There is probably a truth in advertising or a liability issue here, so I'll delicately side step this one.
I'll sleep better tonight knowing I'm absolved for having the nerve to impune the omniscient MR, despite having spent more on MR products and possessing more MR clone hemets, and likely going to spend more than 95% of the commenters that neither have the helmet nor want anyone to think there outlay in cash could have anything wrong with it. If da helmet fit, do not convict, or something like that. I'm back at the altar, and having seen the error of my ways I can go off now an open up my Nautilus. It's a new year, and I had already forgotten this thread a couple days ago after the maturity of head fat, and only came back because some one pointed out a comment on insults. Well, the book is closed. I am STILL getting the other 2 helmets, and they will STILL look great on the shelf next other helmets with differing attributes.

Happy New Year.