psychological flexibility scales (AAQ-II?)

I am looking for measures on psychological flexibility and for some peer reviewed literature that would be a good summation of the current knowledge base on psychological flexibility. I am working with a Research Interest Group (RIG) at my University and would like to give them a quick overview. I am hoping to persaude them to commit to doing some research in this area, but I am the only one in the group with any working knowledge in RFT/ACT. (not that I have a lot of knowledge in the area) The RIG focuses on issues of faith and psychotherapy. I think that ACT's orientation toward specifically addressing values makes it a naturally good fit for our RIG and I think that developing an understanding the relationship between faith and psychological flexibility is a good place to start.
Within the ACT community, is the AAQ or the AAQ-II considered a good general measure of psychological flexibility? Is there a better one? I have come across a few measures, on this site, that are for more specific conditions. But I am looking for a broad measure that isn't diagnosis specific. Any information or insight would be appreciated.