Ignore the proprietary Hercules PC video standard. The Power R was designed to work with a monitor closer to EGA. All the same, it would require modification, possibly excepting the first generation Sony and NEC multisync monitors.
Yes, we did blow stuff up in the 1980s by connecting the wrong monitor to the wrong card... Fortunately, we didn't have an awful kit to blow up and the kit was designed to be repaired.
Even Apple got it wrong a few times. That 19/20 pin floppy drive connector still causes problems, as you know Mac128. The first Mac II fixed frequency monitors used a mixture of D-15 and 13W3 connectors, and it took Apple a while to come up with sense codes and plug and play monitors. In the PC world, things were naturally worse, even when the HD15 VGA connector was adopted.
And your Power R adapter definitely comes from the pre-plug and play world. In that world, computer dealers worked on 50% profit margins, hence the quality support that they could deliver, and made sure that they sold you a monitor that provenly worked with your video adapter. So whilst we don't have that dealer support today, we rely on forums like this.
For information about old monitors, have you browsed net.micro.mac on Google groups yet?