SQL Sentry is a pretty cool monitoring system but there's a downside to having so many knobs to turn: it's next to impossible to find out which knobs have been turned. Let's look at an example.
First I built a five replica multi-subnet Availability Group using my PowerShell module OftenOn. Then I've manually installed SentryOne and watched all the replicas while splitting them between two sites; Seattle and Dallas. I could only get an evaluation license which covers one replica so the rest are not being actively monitored but that's not important at the moment.