Moving Perch folder above public_html

I've read in the notes:

https://docs.grabaperch.com/perch/configuration/path/

I can possibly move the /perch folder up one level and out of the www root, which I'd like to do since I intend on giving content editors access to FTP.

I've successfully moved the templates folder using PERCH_TEMPLATE_PATH however I have not been successful with the PERCH_PATH and PERCH_CORE definitions.

I have read that I will need to change the path to the runtime.php file in all of the files that access it (including login) however since there are parameters involved I would appreciate some guidance.

I know giving directions may potentially render an installation unusable so could write an email to hello@perch.com instead.

Thank you