Take Them for a Spin
While powerful, H&Js have never been an interactive feature that you felt compelled to experiment with. You had to create a new H&J in the H&Js dialog box (Edit menu), fiddle with the values (Edit H&Js dialog box), and then apply the H&J to paragraphs (Paragraph Attributes dialog box, Formats tab).
If you didn’t like the effect, you’d have to go back to the H&Js dialog box, edit the H&J, save it, close the dialog box, and then see how your text looks. The process reminds you of fumbling through the voicemail on your cell phone—back in the dark ages, before the iPhone.
Now, with the new default H&Js, you can try out a variety of options on selected paragraphs right in the Formats tab of the Paragraph Attributes dialog box.
Hit the Apply button (or press Command+A/Alt+A) to see how the paragraphs look with a different H&J. (Too bad there’s no H&J menu on the Paragraphs tab of the Measurements palette to speed this up even more!)
Once you settle on an H&J, you can still fine-tune its settings a little or duplicate it to create a starting place for a new H&J.
Either way, you at least have somewhere to start. When you’ve made up your mind for good, don’t forget to specify your H&Js within paragraph style sheets for consistent application.