I wonder if you could find a TMJ therapist. I once did TMJ therapy where he worked on adjusting my bite by slightly filing spots on my teeth to adjust my bite. It was more helpful than anything I've done, although nothing has ever completely taken my headaches and tension away. TMJ therapists are hard to find. I don't think there are many of them. I lived in Orange County, CA at the time, and could tell you who I saw, but I don't think you live in that part of the country.
Might try googling to see if you're near one though!