Yep 17:1 is the limit of any “wide band” gauge. By using a standalone computer you can see the outputs not visible on the gauge display. This is how I data logged in the first place, the output wire on the aem needs to be interpreted by a computer such as a haltech which is what I use on coyote/modular engines, then you can connect with a laptop and view the data in real time or in logs.
As I mentioned I sold my equipment that I previously used to do the data logging, they are in use on a turbo mustang drag car I built with a friend, so if that car ever comes apart to change it up (or gets wrecked again) then I can get the data logging rigged up again.
Until then the videos with the afr gauge is all I have to offer