From my personal experience the way to go is Gleim. Gleim has every single test question right from the FAA's database with all the answers (including explanations for each answer). The book is broken down into sections as follows:
1. Common questions - which all applicants will see
2. Part 121 - for people who are writing the 121 exam
3. Part 135 - for people who are writing the 135 exam
When you go to write the exam you specify to the tester which part you are applying for and the computer will randomly select 100 questions from the common ones and whichever part you are writing.
When you get to the exam you have seen every possible question. More than likely you will recognize at least 70 percent of the questions without having to read them all the way through!!!
I have used the Gleim books for every single exam I wrote in the US and have passed every one easily.
You simply need to show your Canadian ATPL to the tester to be admitted for the exam.
Hope that helps, best of luck!