Yes I do set up the end time, for example:

This event was over but I could click the hangout link anytime I want, and it didn't tell me anything about the past event.

At this time I will set up another Hangout on air and then paste the Youtube link into Event, just like you said.

But I still think that the Hangout Event could be better if the Hangout situation is bundled with Event time.

Thanks,

QD