Along the San Andreas fault bolt-down is probably a good idea.
I have these in 5x and for some reason now they seem to only offer up to
3.5x (which would probably suffice):
5x works very well for SMT down to 0402. When I have to solder 0201 I leave my reading glasses on underneath it. Those are non-prescription, just 1.75x Dollar-store magnifiers. When having to read schematics plus solder 0402 and up I set it so I can peek above the rims of my reading glasses through the visor and only through my reading glasses to look at the scope or the schematic.
Dentists, dental hygienists and root canal specialists have really cool magnifiers but those are expensive.
The OptiVisor is superb. It's the only visor I know that has prismatic correction built into the lenses, a feature that makes them much easier on the eyes.
(Prism lets you look with eyes diverged, relaxed, as if looking in the distance. Without prism you have to converge, yet, due to the magnifier, your eyes are focused for distance. That unexpected feedback confounds your eyes' normally cooperative vergence and focus mechanisms, the turn-in and turn-out extraocular eye-pointing muscles clash and strain, not knowing what to do, and you get eyestrain.)
The OptiVisor's lenses are glass, too, which means they last forever and never scratch.
Definitely NOT wearable, but allows a lot of workspace in all dimensions as well as highly variable magnification AND capability for video capture.. Set up a Bessler enlarger with digital camera at the film plane. Ever see a (in-focus) 0402 fill your monitor screen?