Diff Editor: Setting to Change Overview Ruler Size

It would be good to have a setting to decrease or increase the size of the diff editor overview ruler. I've looked through several past issues involving it and couldn't find one where this specific aspect was addressed. Specifically, resizing the highlighted part below:

In the example here, it is too wide and I would prefer to make it thinner. I tried changing the vertical scrollbar size setting but it just changes the width of the non-diff segment to the left (with the cursor line) and not the diff-specific segment highlighted (with the red/green decorations and scrollbar).