There's only three entries so far. Based just on them, the tool suggests -- September and October! :-)
Please, everyone who's interested in attending, fill out the form with (at the very least) estimates of when you can attend.
In other news, I have a go-ahead regarding the use of a meeting room in Google's Dublin offices for our needs. This also means having a nice video-conferencing unit for meetings over Hangouts. Projecting to the screen is easiest over Hangouts, too, so attendees may want to have a Google account and Chrome (throwing it away/uninstalling it later, as desired). There are/should be some adapters available for projecting, but I've never tried them out myself.
I'll continue planning as if we meet in Dublin. If you have a particularly strong objection, please let me know.