It sounds like you are into a similar route, Twinkle toes! I recognize many similar experiences, like what you describe about tea tree oil. I've tried most things and this is one of the least effective things I've ever tried (i.e it got much worse with it ...). I wish you the best of luck in fine-tuning your personal recepy/routine! Salt seems like a good thing for problems like this but it is difficult to generalize of course.
Quite honestly I'm stunned that the simple olive oil/natural Sea Salt /gentle wash procedure I use can keep my SD not just "under control", but even restoring the skin into the condition it was a decade ago before the SD problems started. This is something that the standard prescriptions (fungicides/cortisone) never did for me, and it feels really great to leave them behind - for good, I hope.