These aren't entirely directional, they def will need to be pointed at each other but it shouldn't be rocket science getting them to be good. The distance for power is a factor in longer runs, but if you're going to just be running it up the side of a house I don't see the limitation presenting itself.

Placing this in the best-line-of-sight would probably be to it's advantage, it's high-heat rated to 70C attic mounting *may* be an option for you (as long as the attics are vented in the summer, even if they aren't you'd probably get away with it). The Nano is also available, though not through MC right now (I haven't had any problems with them, so I stick with them, the and at about 12 inches can you really complain about size anyway?)

My personal choice would be externally mounting them, but that's just because I like to show off.