I gather from the other thread that this is a card for a fixed frequency monitor.  [ETA: If that is true, then*] you will not be able to drive any modern VGA or Mac monitor, unless it specifically says that it can lock to the frequency of the original monitor.  Screen size (pixels H x V) and refresh rate (50Hz / 60Hz - screens per second) are sort of irrelevant at this stage - it's the horizontal scan rate (in kHz) that you are looking for.  Find a monitor that can cope with that and then sort out any other obstacles that might come up.

[ETA: see note below]