Website Directive snippets customization

Hi there, I'd have three questions regarding directive snippets.

1.) I added a PHP directive snippet with the checkbox "Customer viewable" on, but where can the customer see/set it?
With a Client login I can see only the "Web Server config" for the Apache direcrive snippets.

2.) Is there any option to have customizable snippets with user provided input field?
For both Apache and php values, like the client wants to redefine the apache docroot or php upload_max_filesize, so they could enter it as an input.

3.) Is there any way to activate multiple directive snippets from the client side?
In the Website "Options" panel as an Admin I can add multiple ones, and the config will keep expanding, but on the client side I can only select one, and now I need to combine a lot smaller snippets with all the combinations the clients would like to use.