I certainly don't recommend doing all the questions from either MQ or essentials. Look at a question, if you can map out in your head exactly hat you SHOULD do to get the answer, then don't bother with the question. If you have even the most minor difficulty with planning out the question in your head, then do the question. That's how I approached it and it worked very well for me.
What practice materials do you recommend outside of the textbook and trials?
more trials? that worked best for me, some prefer revision lectures, writing notes (i HATE writing notes!!!), etc. they didnt work for me, but thats not to say that it wont work for you.
I reallllyyyy dislike the idea of checkpoints - because when you come to do the vcaa exams, and take them as if theyre your REAL exam, you can already remember some questions so its like cheating yourself. i avoided checkpoints even against direct instruction from my teachers