Once you create a PDF will any output style the Captured Settings are set to the same options as the style. So in effect the Captures Settings are same as the style you used the last time, which most probably is the style that you use for bulk of your work.
Captured Settings will not change unless you change them manually. Even then, all you need is, select the output style once and Captures Settings will start defaulting to your style.
I hope this answers yor query though QuarkXPress does not allow a default output style.