Positioning the main bar along the auto attack indicator and fervor pips is certainly painful.
However you can get my last
Yessh UI. I added an XLS file that generates the right coordinates. Checking how it works would certainly help you (Feel free to use it in your UI). Just note that my XP bar is 1024 wide and 6 high.
As you can see below I set the height to the screen height (1050) and width (1650) so I can move the pips and auto attack indicator anywhere.
<Element ID="ToolbarField" X="0" Y="0" Width="1680" Height="1050" Detach="1">
Also by default the calculations centers the pips and attack indicator in the middle near the bottom of the screen.
Just remember if you have custom settings for the main bar, you need to set the toolbar size at 1 or it will be somewhere in the middle :
ESC -> Options -> UI Settings -> UI Scale -> Toolbar = 1.00