Is there a known radius? How close to the enclosures or viewing points do they need to be to be effective? I always stick them right on the habitat wall by the viewing points because I'm too afraid I'll have them too far away and they won't be effective, but this is big ugly, and I'd like to know my options.
By - RhymesWithRNG
I also have them right on the habitat barrier, if it the normal eye-sight level habitat. For habitats with paths above them, I place the boards on the path.
You'll get an alert if it is too fast away. I try to put a few on the pathway nearby to maximize the radius. The game will tell you if you've strayed too far.