Hi @willforrestercorbin, here my attempt to explain the workflow in a video.
I show in the video the process to edit the First page template for the Score. You need to repeat the process for the Firs page template for the parts (you only need to edit only the Parts page template, and it will apply automatically to all parts, because they use the same template). To make this, after you are finished with the editing of the full score template, visualise a part (form the layout drop down list menu on the upper part of the Dorico window):
you will see that your page Templatesset says now Current set: Default Part. And this set contains the First page template and the Default page template. Edit the First page template with the same procedure :
Finally, if you want your title font bigger again (we deleted the page overrides, and also this change that you did directly into the layout was so lost), you can go in menu Library > Paragraph Styles and select the Title paragraph style on the list on the left, then set its font size to 36, and this will be the size that you will see on all titles (in score and parts 
)