A couple of thoughts...
Dingo's kid had a TINY curve, which is almost certainly different than your child. He is not a trained therapist.
If this were my child, I would probably pick one therapy that seemed reasonable, and try that. As Pooka mentioned, nothing specific has actually been proven effective at this point. If your child seems reluctant to try something, you might want to consider trying to convince her to do side planks. There is a recently published study on this exercise. What I really like about it is that it requires very little effort.
Side planks article
The other thing to add to all of the stress of this issue is that you should be careful about making too big an issue of it. Some kids take too much parental involvement as a sign that their parents think they're imperfect. Some years ago, as part of the SRS Bracing course, I heard a specialist say that a parent should never insist on bracing at the cost of destroying the relationship with their child. To be fair, however, I have heard from adults who are disappointed that their parents didn't insist on pushing them into treatment (both non-surgical and surgical). All you can do is educate yourself (you've obviously already done a great job at that), and make the best informed decision that you can.
My advice is to let your kid know that this is a serious issue and that you want to help, but that you also value their involvement in determining which treatments to try and that whatever the chosen treatment, it might not work. Unfortunately, once we have a diagnosis of scoliosis, the vast majority of us have to deal with it for the rest of our lives.
--Linda