The tasks which Number 1 assigns are random, in that which one you get comes from a pool of tasks of that same length. To get the maximum number of emblems, you have to complete 4 different tasks, of possible lengths of 1 hour, 2 hours, 4 hours and 6 hours. Which length tasks you get changes every day. Some of the days this is not a problem, like today (June 5th), when I got tasks of length 1h, 2h, 2h and 4h, for a total of 9 hours. But with 6 hour tasks available, there will be some long days.
You have to complete the tasks before the timer resets in order to get the full credit of emblems.
The files imply that there are set length tasks for every day, and Friday the 6th was supposed to be of length 4h, 4h, 2h, and 6h. But as the comments below show, the first task people received was a 1 hour task. So in addition to the random tasks, they are of random lengths.