I haven't played around with <clientCache /> and the C1 Console so I can't give you a straight answer, but if you can configure your global IIS rule to "do nothing" below "/Composite" I would suggest that approach. If you need I rule, then try the
one below - the static files we serve from inside /Composite should not require any frequent refreshing.
<clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="7.00:00:00" />
In general the content served from the /Composite folder (the C1 Console) should not need any global rules on expiration. We have pretty much fine tuned the major downloads, using relevant techniques. Dynamic content is always expired immediately, while
most icons are served via a handler have something like a lifespan of a week. .js and .css files are requested with the full Composite C1 version number in the URL and then allowed to permanently cache on the client. When Composite C1 is upgraded the URL for
those resources are automatically updated.
In general our experience is that "it just works" with default setup. After doing a version upgrade users will be shown a 'version have updated, consider clearing your cache' message, so major upgrades are the only time where a cache flush can make sense.
Your rule about the Visual Editor images make sense - typically this is a very static set of images, but a weeks refresh time is probably not hurting anyone.
Not a real answer, but I hope it is helpful anyway :)