I note that your visa hours in Vancouver is 9 am to 1 pm. How busy is the office?

Generally speaking, it is less crowded during the first hours of every working day, 9:00AM-10:30AM. Applicants are suggested to submit the applications as early as possible.

You are suggested to avoid the following busy dates and the long queue:
1) All Mondays;
2) The first 1-2 days after the holidays.

You can apply for tourist visa one or two months before you go to China, a single entry tourist visa is valid for 3 months, if you apply visa too early, it expires before you go to China.