I think a mix of Daily and Weekly would be good. Always having at least 1 up every day is, I think, a key thing for the forum. Otherwise, it looks like its not being kept up or it was an after thought.

So maybe keep Daily quizzes to the 1 question, 360 seconds limits and then have Weekly quizzes with 4 - 12 (?) questions and up to 600 seconds.... (just putting it out there - not married to the numbers for Weekly).