it [looks like](http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9.4) `proxy-revalidate` is a subset of `must-revalidate` so you may not need to put that in there.

> The proxy-revalidate directive has the same meaning as the must- revalidate directive, except that it does not apply to non-shared user agent caches.