@Crumb
ECS-Agnus and Alice can only directly work with 50 or 60Hz modes, everthing
else is done by a useing a copperlist triggering a premature sync.
So no I don't thing Euro72 and suchlike would help.
Also:
VGAOnly does NOT force anything to 72Hz (little point when standard VGA
GFX-mode is 640x480 in 60Hz), but will set force hsync to 31kHz (normal
"double"-modes are only around 29kHz, too little for cheap VGA-CRTs).
Thisis done by useing part of the overscan area, but since those cheap VGAs
won't allow much Overscan anyways ... :-o