I have GP Premium, and there are no options in the Page Header Meta box other than Page Header location. I wanted to Merge the Page Header and Site Header and experiment with some of the options, but there are no options for me to select.
Thanks. The reason I asked is that I noticed when I wanted subheaders in my blog posts that I had set them as H3 because when I lower the font size of H2 in the customizer it makes my post title smaller than I want. I didn’t know if merging somehow made the post title the H1 tag on that post’s page.