Finding the right hook for adding text to the header template in CMS

[Lynne]

First, don't use global_start, it's deprecated (do a search on it in your files and you'll see). I'd actually suggest global_bootstrap_init_complete otherwise you'll need to preregister template_hook (again, you'll see this if you look at the code).

I put the php directly into the plugin and it worked fine for me. Did you try that?