The other day I came across a Prometheus Exporter for Pi-hole (found in a comment on /r/pihole) that gives WAY more stats/data compared to the InfluxDB script I posted about awhile back. With this exporter, I was able to setup a more detailed dashboard.
Now currently I only have this setup for a single instance of Pi-Hole. I am currently in the process of setting up a second instance as a backup when my primary one goes down for updates. This dashboard can be easily updated to have either a clone of this info for your second instance or a drop down selector for instances. You’ll have to update your queries to support dashboard variables, which isn’t very hard to do.
The dashboard json can be found here.