So, still not sure why one of these:
https://www.amazon.com/gp/product/B00L0YLRUW/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
wouldn't work to extend the signal to your controllers. They don't have huge overhead.
Granted I didn't read the whole thread, I'm a geek after all, we skip to the end.
SM's right on the mesh, don't do it - you don't need it and it's a PITA. I've installed Ubiquiti, I'd spend on that if I was forced.