Deployer, nginx and custom wp-content folder

Hi, I believe I’m having a similar problem to this but presumably not exactly the same as that was resolved. I am also using deployer and have my wp-content path outside of the usual location (and named only ‘content’).

I’m using the following rules:

# WebP Express rules
# --------------------
location ~* ^/?content/.*\.(png|jpe?g)$ {
  add_header Vary Accept;
  expires 365d;
  if ($http_accept !~* "webp"){
    break;
  }
  try_files
    /content/webp-express/webp-images/doc-root/$uri.webp
    $uri.webp
    /content/plugins/webp-express/wod/webp-on-demand.php?xsource=x$request_filename&wp-content=content
    ;
}
# Route requests for non-existing webps to the converter
location ~* ^/?content/.*\.(png|jpe?g)\.webp$ {
    try_files
      $uri
      /content/plugins/webp-express/wod/webp-realizer.php?xdestination=x$request_filename&wp-content=content
      ;
}

These are the results of the three tests:

Testing redirection to existing webp
Bummer. Although we did get a webp, we did not get it as a result of a direct redirection.

Enable redirection to converter?
This works.

Create webp files upon request?
Sanity check FAILED for destination path: Path is outside resolved document root (/var/www/site/releases/6/public_html)

Using the alternative rewrite approach (without try_file) causes the second test to fail also.

Any ideas welcome.