@ryanc That sounds correct based on the descriptions, but make sure that your switch supports breaking out the QSFP+ port to 4x10G because not all of them do. Also make sure to get it coded for your vendor.
@ryanc@kajer My understanding is that pretty much all 2km or less optics are rated to receive their full transmit power. When you get above that, you would need to look at the spec sheet and concider if an attenuator is required.
@ryanc I'm not sure if it automatically does the location, but I think Subtitle Edit is the main open source tool for that. If you haven't tried it already, it's probably worth a look. https://nikse.dk/subtitleedit