After Playing around with all the different presets and editing Arcade 31, VESA 768 and PC CRT 70kHz/120Hz I came to the conclusion this version of Arcade 31 gives the best results for my monitor.
monitor "arcade_31", "Arcade 31.5 kHz - high resolution", "4:3"
crt_range0 31400-93750, 49.50-75.00, 0.940, 3.770, 1.890, 0.349, 0.064, 1.017, 0, 0, 480, 960, 0, 0
It required very little adjustment from the monitor and gave me 480-960 for all my mame games natively doubling everything so that when I add scanlines the doubled lines are blanked out. Everything looks beautiful and 1941/ 384p games finally look as expected when running at 768p instead of being extremely squashed. While Calamity mentioned adjusting for this from the monitor I still will now to get things perfect but at least nothing is off by extremes!
Thank you very much to everyone for their help!!
Next I plan to experiment with the shaders to see if I can get scanlines that show in Vertical games as well as Calamity said earlier the scaling blurs overlays in those stations.