In fundraising we generally use a central banner to store our translations, and then other banners pull from it: https://meta.wikimedia.org/wiki/Special:CentralNoticeBanners/Edit/FR2015_translations
I don't know if it is due to the number of messages, or the fact that many other banners reference it, but adding a new message takes a *very* long time and eventually gives me a "Service Temporarily Unavailable" error. e.g. doing it today and adding the "minimize" message. I haven't encountered this when doing the same on other banners.
However refreshing after this shows the message does seem to have been added, and is working correctly.
Any thoughts? We don't add new messages often, but I'd hate to get to a point where it isn't working at all.