Installing Gitlab and its webserver on separate machines

Hi there,
We have been using Gitlab omnibus on Debian for a couple of years quite successfully and reliably. Our current configuration is a pretty standard one using Apache instead of NGINX as web server. Until now we are running the server in our intranet but now we want to make it public externally. To do this we need to pass through our organization main web server which would allow us to run a virtual host on that server (still Apache) but not to install gitlab directly there.
Is it possible to use gitlab in this “detached web server” mode?
I noticed a couple of things which could hinder this type of deployment but I would like to ask for an expert opinion before going forward:

  1. If the webserver is serve.me and the workhorse is on git.me should I also configure the ssh server to forward the git user from serve.me to git.me?
  2. In the VHost configuration there is a DocumentRoot directive connected to the local filesystem. Is that essential to the operation of gitlab?
  3. I googled for a couple of hours and I found no mention of this type of possible configuration so I’m starting to think there is something wrong with it