Yeah I think a vacformed shell over some kind of gasmask-filter undercarriage might be the way to go (you need that deep undercut in the chin area I think, plus the face looks like a thin "hood" over the open mouth area). But the helmet could still be an assemblage of vacformed parts, doesn't need to be heavy or mechanical.
On the neckseal, yeah I had the same concern. I think there must be some high, cylindrical neckpiece under the helmet, similar perhaps to C-3PO's neck.
I hope the suit was not intended to show bare skin under the helmet from low angles, but that's what we ended up with in the final film anyway. :lol
I suppose some kind of balaclava under the helmet (as clearly seen on the "spacetrooper" with helmet off in ANH production photos) would take care of that, but there does seem to be an armored neckpiece over top of the neck.
Re 1950s high altitude suits, yeah, something like this, which was often depicted as a spacesuit before the realities of actual manned flight had to be contended with. Pix via Global Effects.
- k
On the neckseal, yeah I had the same concern. I think there must be some high, cylindrical neckpiece under the helmet, similar perhaps to C-3PO's neck.

I hope the suit was not intended to show bare skin under the helmet from low angles, but that's what we ended up with in the final film anyway. :lol
I suppose some kind of balaclava under the helmet (as clearly seen on the "spacetrooper" with helmet off in ANH production photos) would take care of that, but there does seem to be an armored neckpiece over top of the neck.
Re 1950s high altitude suits, yeah, something like this, which was often depicted as a spacesuit before the realities of actual manned flight had to be contended with. Pix via Global Effects.
- k