Using Boron for temp humidity sensor

Here ya go:

Each Boron will need it's own Thingspeak Channel ( API Key, saved as myWriteAPIKey ).
Each Boron will publish the API Key, so only 1 webhook is required for unlimited Boron's.
You can update all 8 ThingSpeak fields for a channel in 1 publish, if you wish.
Note: The Webhook doesn't care what you name your Field 1, Field 2, etc inside ThingSpeak's Channel Settings.