I would like to play MAME games on my Killer Instinct cab in their native resolutions. I'm having trouble doing this though.
I am using an ArcadeVGA through a Jpac and I have made sure the settings are set correctly as specified on the Ultimarc website, ie DirectDraw etc. I believe my monitor is Hantarex Polo.

I am using MamePlus 0.132.5.0 and cannot work out how to create individual ini files for each rom. I have come across various resolution tools but the download links seem to be broken.
I have tried setting the default resolution at 640x288 and 384x288 and this creates a picture with no flicker but with a slight wobbling motion on the left side. Every other resolution creates a moderate to severe flicker, but with no wobbling motion, including the Killer Instinct resolution 320x240 (321x240). I have tried adjusting the pots etc but to no avail.
What can I do to play the Killer Instinct rom and other roms so they look exactly like I was playing them from the original pcb? I have played Killer Instinct from the original pcb and there is no flicker.
And what needs to be done to play vertically oriented games at their native resolution?