Setting it to DirectDraw with HardwareStretch off made the game much more precise on Win7. I still think the Mac with openEmu might be a little more precise but it's much closer now. I have to try it again tomorrow but that tip helped a lot.
HardwareSretch turned on with DirectDraw caused lots of video problems which is why I quickly dismissed DirectDraw before. My luck I turned off HardwareSretch this time to see DirectDraw is actually better.
So what is the difference between d3d and DirectDraw ?