Due to the USM drive markings don't help at all. The 5D (without II) does not support live view. Even if it would I would never rely on that. The final picture is out-of-focus if you turn the focus ring by about half a milimeter. That's why it is sooooo important to visually check the distance setting. Even to auto-focus an object in the far distance sets the wrong distance. I work with this lens for almost 5 weeks and see no way to overcome a hidden distance window.
I will work out a tutorial on how to rebuild the distance scale on other part of lens.