This is awesome! The first thing I discovered was how much network noise crashlytics.com was causing. Used AdBlock's[0] DNS proxy feature to black-hole the offending domain (they even mention blocking crashlytics.com in their FAQ[1]).
Note that both AdBlock and Charlex rely on iOS's VPN feature, and only one can be enabled at a time.
[0] https://itunes.apple.com/us/app/adblock/id691121579?mt=8http...