Q. APA format, if more than 6 authors do you use ...
In APA style, if there are 6 or 7 authors, you list all of them like normal in the reference list; for the parenthetical citation just use the first author followed by et al.
If there are more than 7 authors, the reference will be a bit different. You'd list the first six authors, then an ellipsis, and then the final author's name. For the in-text citation, you would again use just the first author and et al. For further explanation and detailed examples, you can consult this page.