Yeah, the sides aren't flat, couldn't remedy that in the modeling stage. But no, the mouth isn't too thin, the ears just throw the whole thing out of whack. The real mouth plate really is quite thin on the real deal, even more apparent now that the HAA helm no longer has the sentai mouth but just a slit. Clear photography is also lacking, to the state where the merge point between the back of the ears and the rear dome on Thomas was filled in with detail from the Medicom figures.
The EL-wired versions they use for the their encore during tours and at the Grammy's highlight the angles usually hidden in the chrome and flashy lighting.
I'd reproduce the Disc versions, but I didn't think the lighting would transfer well to paper form, along with a slew of other details. Guy-man's dome isn't even fully seated within the gold frame in Disc, it sat above with a visible gap partially covered by rubber lining! And of course, for completion's sake, there's also the tubing, the backpacks, the gauntlets and a set of different glove plates for each member.
I've yet to see a single fan-produced helmet that could pass for the real deal. Even the background helms in Electroma were vacuum-formed, with Thomas' missing the rings before the endcap on his ears and Guy-Man's missing the LEDs and rod underneath the ear boxes, and rather sparse wiring on the back of the head. Both were also extremely soft detailed at the join points or even the obtuse points that were even close to 90 degrees. Despite all of them being snatched up at the end of production, even they wouldn't pass as legit.
Sorry for rambling, but this is a real point of frustration for me. I'd love to have an accurate set of helmets, but I can't see that happening without Daft Punk giving out the license for reproductions, as even if someone got a hold of a real piece or the molds for one, they'd be shut down faster than they could produce them.