Ok, so what I did was launch some games, use live edit to size the picture and observe the Nr Pixels and Nr Lines and Wait Pixels and Wait Lines. I did this on variety of games. I ended up seeing that I will need 4 different profiles. 640x512, 640x400 and then duplicate of those but allowing empty space around the borders for games that have overscan. I also have one profile for workbench at 800x600 resolution.
I struggled with the profile creation at first as I couldn't figure out how to save the profiles. E.g. when I was editing Left, Top, Width, Height in the Adjustments window, after clicking Okay the entered values weren't persisted. It turns out that if I mouse click into the input boxes to enter the numeric values the values don't get persisted. They only get persisted if I tab out of the input boxes or if I use the left right onscreen buttons. This seems like a small bug that likely could be fixed.
In games I'm able to use the X key in live mode to switch the profiles, which works nicely. Now, how can I use the Min, Max lines to automatically select 640x512 or 640x400? What range should I use?
Also, how can I update/save profile settings directly from live edit adjustments so that I don't have to manually edit the profile after I exit a game.