Yeah manufacturer's specs sheets aren't detailed enough, but you have to give it to them that customers using custom free-range drivers and apps are rather rare, if not unique to Groovy + CRT_Emudriver users.
AFAIK I am the only active member here to actually use such a setup, if you expect plenty of community insight on the topic you will be disappointed.
So finding a compatible 'plain' flat panel display for this is indeed a gamble. For ViewSonic I believe all of their models listing at least a 56Hz mode in the manual (.pdf user guide) will do the job. But they don't do 4:3 monitors anymore of course.
What about other manufacturers ? that's not documented...
At least that NEC also lists a 56Hz mode,
maybe a clue that it is the same kind of horse as mine.
Maybe.
Today people who want proper refreshes support like on ye olde CRTs but on a flat panel, are supposed to opt for a gfx+display setup featuring FreeSync or G-Sync (and soon HDMI VRR for TVs).
So doing it with a normal, plain one is completely a niche-within-the-niche refined hack job, or as Calamity would say "bleeding edge old tech".
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