Thanks for everyone’s replies. The contact between the shield and the air could be a problem for me because I’m planning mobile use, and the vibration could cause damage to the unit (outside and in), though a shield with “some space” could be worse in terms of periodic crashing around inside.
Most shields out there are designed for smaller sensor-only units, not the sort of hybrid we’re getting from WeatherFlow … so the shields are too small a diameter inside or not tall enough or both. (A future option to remove the base sensors from the Air enclosure would be nice … some day?). Unfortunately this rules out shields from R.M. Young, MeteoShield, COMET, etc.
I see there is already a page on this …
Photos of Air and Installation
And some other links -
http://www.digitalurban.org/2018/09/3d-printing-a-radiation-shield-for-the-weather-flow-air.html
https://jimboombaweather.com/station/stevenson.html
http://users.otenet.gr/~meteo/project_radiation-shield.html
Mine would be “well ventilated” so I might look for a sturdier version of something like this: https://comunidad.leroymerlin.es/t5/Proyectos-Talleres/Garita-para-estación-meteorológica/idi-p/161088
Brian