I’ve been working with a studio currently developing several armors for their game. One issue we came across was helmet clipping. I remembered that Oblivion and Skyrim didn’t have morphs on their helmets and sometimes they would remove the head all together on closed faced ones and leave only black.
This ensures nothing will clip and your helmet doesn’t end up looking all weird from all of the morphs etc..( ie. a helmet with large cheeks and protruding nose.). It’s best to limited your face morphs to a reasonable distance.(just before clipping starts).
I’ll probably look into re-weighting/tweaking any closed face helmets later so they are re-sized a bit larger.