Without getting too technical... it's up to you
A batch of yeast is only going to eat so much of the sugar that you put into the beer. When the yeast is done it settles to the bottom. Flavor wise, with the time frame you are talking about, it doesn't matter if it finishes in the first fermenter or the second one. Many people use the secondary to extend the process and get some additional clarity. With a Hefe you aren't worried about clarity, so it really is up to you.