HTTP: Combining expiration and validation caching

I'm having trouble formulating HTTP cache headers for the following situation.

Our server has large data that changes perhaps a couple times a week. I want browsers to cache this data. Additionally, I want to minimize latency from conditional gets as the network is unreliable.

The end behavior I'm after is this:

1. Client requests a resource it hasn't seen before.
2. Server responds with resource along with ETag and max-age (24 hours).
3. Until 24 hours has passed, client will use cached resource.
4. After the expiration date, client will perform a validate request (If-None-Match: [etag])
5. If resource has not changed:
   • server responds with 304 Not Modified
   • client is somehow informed that the existing resource has a new expiration date 24 hours from now
   • return to step 3

Boiled down to its essense... can a 304 response contain a new max-age? Or is the original max-age honored for subsequent requests?