To avoid this particular engineering problem I imagine space binoculars would just come with a screen so that you can hold it at your preferred viewing distance :P I'm imagining something akin to a camera with a telephoto lens
Edit: an example (not telephoto but an example of what a screen view through a high optical zoom camera lens would look like)
Something around the size of this camera is probably reasonable to mount on the helmet which would keep it fairly stable.
8x42 binoculars offer 8x optical zoom from my understanding and the camera in the video goes up to 83x so it should be simple to replicate the zoom level.
If they went with analog binoculars they would still likely be the kind which you press against the faceplate instead of held out in front of you though. As mentioned in the comment, stability is important when looking at magnified things with handheld devices.
Rifle scopes are designed to be viewed at a similar distance from the face and maintain a fairly high angular field of view.
You can see what the view through a scope looks like above. Also it would probably be a monocular because there's no point in 2 lenses if you can't get one image for each eye.
What I'm getting at is that they have the technology to make optical devices for a variety of viewing distances and so it's unlikely that the viewing distance will be a device limitation.