Moving hotbars without HUD Layout.

I searched all over unsuccessfully for this, and finally figured it out myself, so I'm posting the method here for future searchers.
If you want to precisely align your bars without repeatedly going into HUD layout, do the following:
Go into System, Character Configuration, Hotbar Settings.
Turn on "Display Hotbar Numbers" and "Enable drag-and-drop repositioning"

Now, the bar numbers serve as handles to drag them around with. Arrange as desired, then turn off drag-and-drop (and number if you want) to make sure you don't accidentally move them.

You get much better positioning when you can see the actual bars and contents than with just the outlines in the HUD layout.
(Everyone but me probably knew this already, but a few new players may need it.)

It's also useful to know that you can use the numpad on a keyboard to nudge any HUD element 1 pixel in a direction.