By the way, I just did something similar in this plugin https://github.com/Hube2/acf-options-page-adder. I added 2 wysiwyg fields to it. All of the settings in the the plugin are actually store in post_content of my post type, this speeds up loading because I don’t need to get the values of each field.
You can see where the stored values are displayed in the function customize_end() on line 677 of the main file. I actually use get_post_meta() to retrieve the values so that part probably won’t help you, but if you want to look at that the function that gets the values and stores them in an array is on line 578 build_options_page_settings()
