For the second week of the holidays I did a practice exam for Methods under exam conditions, and for the first exam (the one with no calculator), I got about a score of 33/40. How is Heffernan in terms of complexity and how does that relate to a VCAA exam performance?
They are usually much easier than VCAA
Look at the ones from previous years.
Yeah, previous year ones are easier, this year they make harder but still not as hard as iTute and Kil
Actually I don't like to do iTute because they are so hard

and it makes me lose confidence
In some prac exam, they give questions with symbols and formula somewhere else, out of course. I even don't know what symbols in the ques mean, how can I do it?
Good companies include Heff, Mav, TSSM, Insight, Kil, Neap, Engage (imo though)