Can I use SINAD for THD+N measurements? Are they inverse of each other?
So I guess I should have looked around a little better. I've found that SINAD and THD+N are reciprocals.

These references were useful:

https://www.ap.com/technical-library/more-about-thdn-and-thd/

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.476.1903&amp;rep=rep1&amp;type=pdf