Nice chart.
I recently started to play with averaging multiple sensors in HE to look at indoor and outdoor temperature, using @Cobra 's driver: Average All. I still need to send these through via the maker API. Even though I could do this calc in Influx / Grafana I feel the driver gives me more flexibility with HE dashboards, etc.
I also like the focus of the dashboard, I'm still toying with how best to lay mine out. Will try and post some pics in the next day or two.