This is some illumination here. Thank you, FBX! I was close with my settings, which work great on 320×224 games, but dialing in for the 256×224 games is a real treat. I also took the opportunity to index my EDMD per game native resolution, as I see you have yours indexed – one folder for 256×224 games, and split folders for 320×224 games (too many of them to fit in a single folder).
I took it to line5x @ 1600×1200, which is my personal preference for the best looking all-around, based on your optimizations. I tweaked the backporches, and am now using the masks which I hadn’t been doing previously. That really does add a nice improvement, keeping the unused space out of the picture (no pun intended).
I’ve since started a repository of all new optimal timing research based on the 0.81 firmware. I even found some slight tweaks to improve the Genesis/MA profiles too. All are now text files on my web page here: