I contemplated cutting the upper part of the facemask to extend the height of the eyes a bit, but the angle of the eyebrow line is off too, not just the vertical height of the eye lenses.
Even maybe just blacking out those upper "eyebrow" rim lines above the eye lenses (so letting the "eyebrows" of the dome take over) might help. To me those upper high gloss eyebrows on the top of the eye lenses make the eyes a bit too small.
I do think widening that stepped strip between the eyes would help also. It needs to be more dominant. I was going to insert two thin strips of styrene and paint them gunmetal.
I stopped work on this thinking that TooMuchgarlic's Vader helmet was coming really soon (so little point trying to futz HT helmets - as they are overall slightly too large anyway) but that project just seems to stay in the slow lane. Maybe I should revisit this helmet. I do like the HT ESB Vader overall - it has more Vader vibes than the ANH versions, even if the ANH sculpt has less (or at least easier to fix) inaccuracies.