Give this setup a try.
It's a HighGfx 1024x768 workbench config. It gives full screen PAL at a smooth, no stutter 50hz. It does NTSC at a smooth, fullscreen 60hz too.
You'll need to have HighGfx, PAL and NTSC in your DH0
evs/Monitors folder.
You'll probably need to set ScreenMode Prefs to HIGHGFX:Super-High Res Laced to 1024 and 768.
You may well have to set the Overscan for PAL and NTSC in DH):Prefs. On my monitor (a Viewsonic VP2030b) the PAL overscan is (72,14) and NTSC is (72,22). These settings affect the position of PAL screens that open up in Workbench. The H-Offset and V-Offset settings in Indivision Prefs affect the postion of PAL and NTSC screens that open up outside of Workbench (ie most games).
There is no guarentee this setup will work at all with your monitor.