Thanks rlemmon. I did see those notes on the ultimarc site and have been using them.
The one setting that I'm a bit confused on is Direct 3D. I am pretty sure it should be off. It has a major impact on the image, so I'm also going to ask Andy to confirm that it should be off. With it on, it appears to map the orginal horizontal scan lines onto the images as a 'texture.' It can also create a distortion effect when forcing a resolution. With it off, there are no legacy horizontal scan lines and the images, such as text, are completely solid. I understand that this latter effect is due to the high dot pitch of modern PC monitors versus old low-res arcade monitors.
I will post some pics once I think the settings are correct.