Pages administration documentation needs clarification

I'm working with a customer in https://gitlab.zendesk.com/agent/tickets/19420

The Pages docs at http://doc.gitlab.com/ee/pages/administration.html are not very clear about when pages_nginx shoudl and should not be disabled. Can't users use pages_nginx if they're not using HTTPS? The docs suggest to disable pages_nginx in this case, too.

What needs to happen to support user-supplied SSL certificates? @jnijhof told me that pages_nginx has to be disabled to support user-supplied SSL. On top of that, the port for Pages should be a higher port, and a load balancer should proxy 80/443 back to those higher Pages ports. This is not really made clear in the docs and to be honest, I'm still not clear on everything that needs to happen. Maybe we need a note in there, too, that it's OK to use pages_nginx if all of your Pages sites will be at the *.pages.domain and using the same SSL certificates.

@axil Can you please help clarify this? Thanks for your help.