When I mentioned on another forum that 3D gave me mild headaches, somebody suggested it might be due to a low refresh rate of the glasses and people with particularly old C.R.T.s had the same problem.
The number might be listed on the back, alongside the power specs. Nominally an N.T.S.C. television would have a 60hz refresh rate, allowing up to 60 F.P.S. since it corresponds to 120 volts. Some computer monitors allow you to change the refresh rate via the computer's settings but I wouldn't know if a television with fixed resolution input would allow the same, since it seems like it's based automatic signal detection. It may depend upon the specific model.
Hopefully this gives you at least a place to start and if it can't be helped, maybe you can at least find somebody who'll be able to similarly appreciate the set's picture quality to you who'll take it off of your hands. Vintage video game players in-the-know love these old C.R.T.s and they'll probably never be made again, but that's a subject for a different thread I suppose.