Where would I set the top and bottom staff margins? In Sibelius, I would do this in Document Setup/Staff Margins. In Dorico I can change the top and bottom margins in Layout Options/Music Frames Margins and in the Master Page Editor. which would be the correct place?
I would go for Layout options → Page setup → Page Margins.
This (I think) is the global margins of the layout, which makes sure nothing passes it.
The music frames margins found in Layout options and Engrave mode refers to the distance between the music and the bottom of the music frame.
Thanks, Anders.
I decided to set the bottom and top staff margins in the Master page editor after all because it makes the most sense. Using the page margins for this would also change the position of the page numbers which is not what I want. Also, adjusting the top and bottom margins in Layout Options/Music Frames Margins would give this distance also in separate drawn music frames which would give too much empty space around the music. I ended up with setting the Music Frame Margins to 0 and the top and bottom frame distance in the Master Page to the distance I need, which in my case is 20 points.
Isn’t it great having such a flexible tool that has a solution for every scenario? 
It surely is 