Hi! sorry for commenting so late –well it’s still November so i dared– but as an additional sugestion to the calculation form the Team’s Product Manager offered, you can approach a similar solution if your header’s fixed; by marking the option ‘Top of next section’ in the scroll properties (Inspector Panel) of your header, and then making your section the height of the viewport (100vh).
This way your header covers the section and you don’t need to do the calculation.
Though you’d just have to make sure the area of the section covered by the header is empty or doesn’t contain anything important; or may not be the best approach if you don’t want your header to be fixed.