I'm running mame148 default settings.
I've had a look at all the files in /hlsl and in /docs. Not sure what I should be changing but mame64.exe -video gdi has made the graphics how I wanted.
The gameplay feels slightly different though. It's running 100% but feels slightly unresponsive, maybe I'm just tired.
Windows video options
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-video <gdi|ddraw|d3d|none>
Specifies which video subsystem to use for drawing. By specifying 'gdi'
here, you tell MAME to render video using standard Windows graphics
drawing calls. This is the slowest but most compatible option.
Specifying 'ddraw' instructs MAME to use DirectDraw for rendering.
This causes MAME to render everything at a lower resolution and then
upscale the results at the end. This produces high performance,
especially on older or low-power video cards, but has a noticeably
lower output quality. Specifying 'd3d' tells MAME to use Direct3D for
rendering. This produces the highest quality output and enables all
rendering options. It is recommended if you have a recent (2002+)
video card. The final option 'none' displays no windows and does no
drawing. This is primarily present for doing CPU benchmarks without
the overhead of the video system. The default is d3d.