Attaching a thermostat probe to a vivarium

What are some good, non-sticky ways to attach the probe to the walls of a vivarium? Also, should I be measuring the heat in the vivarium from under the hides? (E.g. If on top of the hide it is 37 degrees but inside it is 32 which should I be basing my temp readings off?)

Thanks. :)

Hot glue 😋 on the wire, not on the probe itself.

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