Is the recommendation against installing in the attic due to the temperature? In my case, the attic is part of the conditioned building envelope, so the temperature should always be within five degrees of the house temperature, i.e., between low 70’s and low 80’s. Humidity in the attic should also be close to the humidity in the house.
Putting them 50′ apart should be very easy. That means that all wireless devices should be no more than about 40′ from a M1XRFTWM.