If used around an observatory, I think it should be mounted closer to the ground, or at most half way up, and as far away as possible from where you might be standing, or your work table & computer. Otherwise, the unit might pick up the observer and/or guest’s body heat and breathe.
If too high up, close to the top of the wall, it might be influenced by Venturi Cooling from even the slightest winds curling down over the edge.
I suppose it depends on what environment you are interested in monitoring.
Maybe it should be mounted as far away as possible from indoor activity – perhaps outside the observatory, halfway up the wall, and shielded from direct wind gusts, using an open “container”.
I don’t have a Migbox, but do use a couple of (remote) T & %RH data logger sensors – One, permanently exposed outdoors, is kept inside an opened zip-lock bag for shielding from winds, on a bush branch about 10 feet from the scope, where I won’t come near it. Another is fastened to the mount’s tripod, on the leg away from where I might possibly be standing for a moment (rarely actually). Its readings are only for comparing to the other unit’s true ambient outdoor conditions at some distance, against my “UNDEWER” T & %RH operation, keeping the scope dry, while under a tarp.
I feel, for greater accuracy, the sensor in an opened zip-lock pouch, somewhat distanced away from the observing spot, is a more reliable measurement, than one actually inside an observatory shared with people and powered equipment.