Just looked up Tildren, it sounds very promising, but it will take time to work. In the meantime I would still look into the barefoot approach for navicular problems and, as Bondre stated in your other thread, really look to learn it myself, especially in your situation with shortage of farriers. And not only that. I could imagine that he will not appreciate having shoes nailed on, since he is in pain already. Another, rather nice, side effect of doing your own hooves..... it will create an even stronger bond between the two of you.