One way to reduce the width is by stacking siblings on top of one another. You would tend to do this if there are particular siblings whom not much was known, or aren’t so important in a particular chart. To do this, click on the person in question, so they are active, then either click the “…” grey edit button, or right-click on them. This will cause the following menu to pop-up.
If “Start sibling stack” is selected, the person will change to a stacked view.
Then select the next sibling, click their “…” button, or right-click on them, and on the pop-up menu select “Continue sibling stack”.
Do this for the next few children, will save quite a lot of space.
You might need more than one sibling stack to accommodate all of the children. You can start another sibling stack by using the same method, but selecting another “Start sibling stack”.
Siblings can be un-stacked, but again using the “…” button, or right-clicking, and selecting “Don’t stack sibling”.