pro-actively check for specific updated content

Another thing to think about is setting the http-acceleration profile to cache pages indefinitely, and then using an iRule to invalidate the cache (making sure you restrict who can invalidate) and force the request to be sent to the origin web server ie.

when HTTP_REQUEST {

     Check for expiration cookie from CMS
    set fExpirePage 0
    if {[HTTP::header "CMS-Expire"] ne "" && [IP::addr [IP::remote_addr]] eq "10.10.10.10"} {
         Expiration cookie is there
        set fExpirePage 1
    }
}
when CACHE_REQUEST {

     Expire this object
    if {$fExpirePage} {
        CACHE::expire
    }
}

You could use this in conjunction with the cache-buster query parameters.