@Bozo_Cyborg I appreciate it! This is what I hoped for when making this thread because when I was setting things up I also found information very scarce and made a couple mistakes that could’ve been avoided. I may come back soon and see what I can add to my OP.
@cornerstone I believe so I’m not sure when the last you looked was and I may need some help understanding your question. I think you may be reffering to the feature groovymame has where it can generate new resolutions on the fly, I don’t think anything like that has been added to Retroarch. Personally I don’t use the auto generated resolutions because I never did figure how to set a profile that would generate modes automatically that still fit the screen how I liked, I prefer to manually add the resolutions and change the porch values for the best overscan cropping. Retroarch does still allow for resolution switching provided you have all the necessary modes installed. You can use either super resolutions (i.e 2560x240 & 2560x480 mostly, the width value is adjustable in the retroarch config) or you can use native resolutions. This all works really well!
Until I come back to update the thread possibly here is a thread on the libretro forums meant to contain a lot of information regarding CRT emulation specifically with Retroarch: https://forums.libretro.com/t/15-khz-crt-documentation-wiki/15671/4