The review courses were initially way too optimistic about how much time to give the WC for BEC.  I think they were saying something like 10-15 minutes per.  I realize that it's only 15% of your grade, but those suckers are time consuming!  You have 3 hours to do the whole thing, meaning 72 MC questions, plus them.  IMO, there's really no reason that you need more than 1.5 minutes per MC question, and even with the most conservative, lazadical attitude, that would give you an hour for the essays.  And you'll need every minute of it.  So I'd say that you in no circumstance should give yourself than an hour for the essays. 

You remember middle school and those statewide tests.  Read the question, think about the answer, write an outline on your sratch paper, write your response, proofread it, and make sure it's perfect. It might seem a bit silly to spend 33% of your time on 15% of the points, but it's a much more time consuming process than the MC questions.