I converted three arcade overlays from john merrit to 16:10 resolutions, outrun, mortal kombat 4 and shinobi.
Mortal Kombat 4 retroarch settings: integer scale off, viewport x 256, viewport y 89, viewport width 1168, viewport height 871 set overlay scale to 1.02 or 1.03
Shinobi set aspect ratio to 4:3 and turn integer scale on also if needed play with overlay scale to fit gameplay area
Outrun set aspect ratio to 4:3 and turn integer scale on
http://www.mediafire.com/file/3d3vkri8hp4bi6o/Arcade_1610_overlays.zip