The testing is done, the verdict is in.
I have run the Zeiss - Eye Mag Pro F 5x @ 235mm (9.25inches) through their paces on many watches, including several Analog Quartz movements with very small gear trains.
So what do I think? ....
These are the BEST optics for working on watches bar none! I will never, and I mean NEVER, go back to using a standard monocular eye loupes again; except on inspections that require the extreme magnification of a 20x to 30x loupe ... which is rare. The clarity is so good that I don't even have to swap to a higher power loupe to locate the tiniest of pivots, even the tiny rotors in Quartz analog movements ... this set does it all. I have shown them to several professional watchmakers, who have been in the trade for decades (some as much as 50yrs), and they are astounded by the Eye Mag Pro's clarity and comfort, and are looking into getting themselves a pair.
Believe me when I say there is nothing like working with stereo vision that moves with your head movements, and gives complete depth perception at all times. If you can afford to buy them, DO IT! And if you can't afford to buy them .... SAVE! :)