I have the same problem on 1080p screens. Some monitors will allow a 1:1 pixel aspect ratio, but my CFG73 (slightly newer version of yours) doesn’t allow it either. PAL lines up perfectly with V Active 270, but I could never really get uniform scanlines in NTSC unless I used 5x 1920×1080 on the OSSC. As you said, the problem is that it crops the image vertically also. It’s not noticeable on my B7 because it’s 4k, so they just seem to look a lot more uniform on that display no matter what.