Timetable UK time is EST plus five hours. PST is EST minus three hours. Sometimes people are at competitions, or travelling and can't make the date, so don't rely on it every week. Also, people drop in and out all the time. You can send private messages, but etiquette is that almost every message should be public.
People can choose to ignore private messages.
Argument, debate, discussion, flirting, disagreement, setting up appointments, boasting, that's all good fun. You don't have to use it if you don't want to, of course. Likewise Yiddish and Strine. You'll find the Web Site Chiming Clock in there, you might say hello to her. She'll also tell you the time if asked properly.