The Libre1 starts overwriting older measurements if you don’t sync for 8 hours. I sure hope they fixed that in the Libre2; what does the manual say?
Regarding alternative apps: If all you need is an app that can scan the device, capture notes, and that lets you export your data, the official app seems like the way to go. If you need to manage your blood sugar in real time (incl dosing insulin), other apps have more bells and whistles to help with that. Tidepool lets you “donate” your data for research, but maybe you can still do so by uploading the LibreView .csv…
Not really a hack, but a common mistake is to not discard instant readings when looking at historic data. Instant readings are extrapolated, and often way off. Other than that, see my project log 