It has taken me a few days to get back to you about this, and I apologize.
I know I worked on the CNIB course practices May through August of 2020. I *think* I worked on those practices about five hours each week. Then I took some time away before preparing the Pretest. Preparing the Pretest – including a sort of "one-woman team proofreading" where I recorded myself reading the braille out loud and then played back that recording as I looked at the print – took me at least two weeks of maybe two hours each day. I heard back from CNIB in a week about my Pretest results but had to take some time to focus on other work stuff before completing the final test, which I think took as long as the Pretest to prepare.
So, I would *estimate* I took a thirteen-month span with a total of 60 hours worked to complete the CNIB course. That is a rough and probably ambitious estimate. I would not be surprised if it took someone 100 hours or more to do the practices, pretest, and final test.
I was helped by moving through the practices with a colleague. We exchanged error reports after proofreading each others' practices and discussed sticky issues as we encountered them.
I hope that helps. Please let me know if you could use something different or more.