Well .. the problem was, I was forever on my hands and knees moving the V-Hold, switching between Windows / Mamewah, as there was no spot on the pot that would keep both in sync. Also, in 800 x 600 Windows through the ArcadeVGA / JPAC looked absolutely awful .. the refresh rate was giving a strobing effect and the text looked blurred.
It's more of a compromise than a desired resolution .. both Mamewah and Windows look superb now though at 640 x 288. The trouble is, any time I want to make an adjustment in Windows I have to switch back to 800 x 600 as you cant see all the options / boxes you need to. Someone else had exactly the same problem, it was only through his posts that I found the solution .. I was about to hack open my cable. The monitors brand new, and I've had no problems with any other system .. all have worked seemlessly, so I guess it's just a quirk of the combination .. AVGA / JPAC and my cab?
What's the normal resolution to run in?