Use your phone’s permission system, look at the app’s permissions, and set them as strict as the app will allow you to while continuing to function. I don’t see any particularly scary permissions that aren’t optional (looking in Google Play/the Android permissions set).
Pretty much anything beyond that you’re wasting your time unless you want to carry two phones.
Edit: I see you went with Shelter; hadn’t heard of that either. Probably overkill, but as long as it doesn’t cause problems/the app works for you, go for it.