We're getting somewhat off-topic, but I did want to address it quickly. Over the years, vendors increased the size of their domes because they were challenged by rear-of-head coverage. Lengthening flanges and over-sizing the domes was actually not necessary, and a lot of that is corrected by proper dome orientation. The proportions of the mask to dome have thwarted people over the years, and some of that is due to mask and dome sources available at the time.
The closer you get to the helmet, the face will be bigger in proportion. The farther you pull out, the lens (assuming 35mm+) will pick up more lateral detail, so Fett, Vader, Stormtroopers, etc. will appear wider. You'll see a bit of this even with consumer cameras.
Here is a comp of Quasimodo: 18 feet vs 6 feet. I think Poopa will like the big dome look if he stands far enough back.
http://i18.photobucket.com/albums/b...o/quasimodo-18-feet-vs-6-feet_zpsb37d660c.jpg
However, if at 6 feet, a helmet has the proportions on the left, then I would propose that the helmet is inaccurate.
Here is an additional read:
Face distortion is not due to lens distortion | Daniel's Visionarium
Okay, let's get back on-topic.