I have the original Atari ST manuals if you send me your e-mail address I will scan the page with the monitor pinouts for you.
STs use a scan rate 1/2 the rate of vga and svga. To get a decent picture you need a multiscan monitor that will scan down to 15 Hz or an old rgb monitor. I live in the UK and use a Phillips with a SCART plug but an old Commador or something similar should work with the right connections.
