I believe it's fairly common, at least for Americans, to tip favorite stewards, bartenders and waiters in addition to the expected "gratuities", however paid, without regard for where they go.
I lean heavily towards the maltier and perfectly balanced Bavarian lagers, Marzens, festbiers, doppel bocks, dunkels, monastery beers, etc. many of which have been a "fad" for centuries.
Yeah. It was the standard pour on our river cruise. Don't know what they served when asked for a dark. Homelands I think Carlsberg was poured and I would get Carnegie Porter or Grimbergen.
Typically a quite good lager when I would ask for a beer. When asking for a dark beer always a very decent bavarian or porter. If you can tear yourself away from the IPA fad you will do just fine. You can always get anything available off of any list as per above.