Driving "Arcade CGA" monitor safely
This is basically a TV Video [SD] monitor.
The first PCs used this 'resolution'.
Treat it like composite video and you are good to go. 
NO, there is no better resolution possible

Interlacing actually halves the refresh rate. EG: 1st odd lines frame is 1/60 second, second even lines frame at 1/60 second; Complete frame is produced every 1/30 second.
That's 30 Fps. Drop frame is common and is 29.97 Fps.