Using this guest page cache is a very bad idea in my opinion.
Yes, what you wrote can probably be done - I don't know how, but you try reflect on a possible situation (I have observed such - and with less cache time) - what I mean.
You want to use one hour of cache - but after that one hour, if a user with a slow internet connection is the first creator of that page - then for the next one hour, your guests will see a very bad version of your site... no matter where ( in the case as you say - cloud cache) they will receive this.
If you want your guests to receive limited, but high-quality (and probably much faster, due to the limited content of your main site), then use conditionals of the type - "if the user is registered - this, if not ... " etc. This practice will save you resources for guests, and better performance such as site loading speed for example.