Wait wait!!
Duck, 23:00 for an event that can last 2 hours or more means 1:00 of monday for the end, not including eventually the work on AAR, and the possibility of a later starting time for any reason.
Monday is a work day, and a lot of my squadmates (including me) have to go in jai... ehm... at work, woking up early (6:30 for me).
22:00 or 21:00(better for eastern countrymen) is a better time, IMHO.