So I don't know the details of the NFZ DJI app stuff. Haven't really (fortunately!) had to deal with it too much. I'm not quite sure what you mean by the "15 degree no fly zone expansion" either.
UPDATE: Okay now I see that the 15 degree thing is part of the DJI NFZ stuff. I'm relatively new with the Mavic myself so obviously I need to make sure I know what's up w/ that more before getting unexpectedly screwed on a job!
I'm leaving the rest below as it's still good if you want to know the actual airspace rules.
The best bet if you really want to know your airspace is to learn to read the official FAA Sectional Charts. Best site to look at them is
SkyVector: Flight Planning / Aeronautical Charts - I also use GAIA (iOS map) to layer sectional charts over satellite maps
Watch some YouTube videos to learn how to read the sectional charts. They're complicated at best but in the end are the best way to know the FAA airspace limits (which I think is what you're referring to re: the height of zones..)
Here's a few of the videos I watched prepping for the 107 test
Otherwise, Airmap.io on web and iOS app as well as Kittyhawk iOS app have good maps (Kittyhawk has already integrated the new FAA facility maps). Sorry if you're on android, I have no idea which apps are cross platform