Trying to get a ToC to work properly in multiple PDF compiles is a nightmare. I finally figured out that the easy way is to copy / paste it into a front matter, then create a ToC style for it. Applied the style. Then going into the different PDF compile steps, override the style, and set the right tab.
However. If you just override the style and drag the right tab around and hit save, it does not save. You can change nearly anything else, but it looks like dragging or adding/removing any tab features does not save. It doesn’t recognize the style changed at all, in fact. Very frustrating, and led to me wasting a few hours trying to figure out why my ToC was always breaking over to the next line.
For those affected by this: If you select the style override, select some of the text in the example window, CHANGE THE FONT SIZE, then set any of the tabs, CHANGE THE FONT SIZE AGAIN. Save. Then come back and change the font size to what you want, the tabs should be saved. Super frustrating.