Scott,
I think muscle testing can be quite effective. I have a friend and colleague who does muscle testing almost exclusively and his diagnostic ability is amazing. He has been doing it for years and is a real pro. Back when I had a more traditional cranial osteopathic practice I tried to learn his approach. I was never able to pick it up confidently and found overtime that to dabble in it just didn’t serve my practice very well. At this point I do not do it myself, but I believe it can be effective. I have always been a fan of homeopathy too.