Modeling Test Durations

Have been having a conversation around what the ideal modeling test duration is. I see two major options.

1-3 hours: Specific duration depends on the difficulty of the model you want the candidate to build. I think a good rule of thumb to give candidates, take your best associate, have them do it, double the amount of time that it took them. Doing it over a shorter period (probably ideally proctored) gives a more complete picture into the candidate's raw capability

A few days - 1 week: You want the candidate to give the case study significant thought beyond the model. How should we evaluate the deal, what questions to ask, what else can you do with the data that I provided you. If I give you a longer amount of time, my expectation is that you are ready to have a very in depth conversation on the deal and you have done analysis to support your view of the deal. Potential candidates can also show how badly they want this job, how hard they are willing to work, via how much time they put into the case study 

What duration have you found works best for evaluating the best associates? Any arguments for or against specific model test durations?