Depends on the cleanliness of the facilities. Home im sitting. Nice clean restaurant, im sitting, grimy dive bar, im standing. Porta John without a urinal, def standing.

And you can fix the stream issue by by giving the tip a little squeeze/ roll before you start, opening up/ unsticking the walls of the urethra (really the fosa navicularis, a widened cavity in the tip, at the end of the urethra) ensuring a uniform stream.