de0u
Confirmed by app developer (meowsbox). Respect to google for trying to tighten the security belt, but they've taken the "All the time" option away from developers unless they are fortunate enough that google allows it for them. Crappy thing to do for developers and users. It's my damn device and I should be able to do what I want with it so long as I demonstrate an understanding of the repercussions.
In the offhand chance anyone else stumbles upon this thread, meowsbox suggested downgrading the app to the previous version and this workaround is effective.
https://www.meowsbox.com/sites/default/files/media/apk/BluetoothGPSOutput_RELEASE_76.apk
I uninstalled the app and reinstalled with that apk and was able to choose "All the time" in the location permissions.