Depends on the tower. North is 9:30am-11pm, south is 9:30am-5:30pm. Edit - forgot to mention they close the entrance 30 minutes before, so 10:30pm and 5pm really.

You can basically go up.

Not much, the most could be 20 min or less

Yes

I agree. Even today's response should be dispersed and released from the morning before it is full. Do not damage the people downstream.

North side

It's open on the 1st but closed for the 2nd and 3rd.

Free.

It is 11 pm. Entry is until 10:30 in the evening. In the evening, only the North Observatory is accessible, and only the entrance to the underground entrance leaves. Please note that during the day, the entrance and exit floors are different.

Other than certain holidays around the new year, one of them is open everyday till 11.