If you ever need spares for that old 900fsk, give me a shout. I have lots including a horizontal omni, a 120deg DP 12db pannel and more than enough APs, SMs, 13/17db yagi’s and integrated antennas to start another gurilla wisp!
If you decide to try the dual yagis again, try to space the antennas more than 2 wave lengths apart and ironically despite the sslant orientation, you want virticle separation. At 918Mhz this is about 13 inches. This way you dont have combined losses of the antennas magnetic fields. If you were trying to combine two to a single feed and the antennas would have an identical magnetic field then being half to one wave length would be ideal, but I found the injection losses on two 17’s with a balun splitter to give only 2db additional gain. Not enough gain for the costs but was worth playing with.
If your lone customer needs more bandwidth, I would sync two APs on an LACP port channel and two SMs on her end with a switch to complete the lacp bridge. With 3 available channels you can go up to 3 links and she could have almost 10/2 service.
We have a few clients installed in trees. Well 3/4 ready-rod through the tree and a pole clamped to the tree to get above the trees. Not ideal but on a 5.8ghz f180 at 7miles we are able to provide 98% uptime to that client with down times due to the 70mph wind storms we get.
Yeah, KP does that, it should be left and right slant or simply A and B.