hey,
i am a transfer to penrith high school this year (year 10) and let me tell you, unless you are already coming from a semi-selective school it isn't really worth it. i passed up girraween because i thought there would be less competition, but at penrith you have to sit exams to qualify for subjects like chemistry, physics, ext 1 math, english.... two people have already left my grade this year because of the qualifying exams and im finding people in my grade on these forums trying to figure out how to transfer to schools like baulko. personally i wouldn't even try and go for girra instead. i know applications just closed but seriously... don't think that penrith isn't competitive just because its low, because the departments pit students against one another to qualify for popular courses. i am actually blacklisted from extension 1 english, chem, physics and potentially ext 1 math its so insane... i literally need to get 100 on my term 3 math exam to even be considered... they don't listen to student protest either, its really not worth the stress. you could probably do better at any comprehensive school doing chem, physics, and both extensions. you have to fight for your courses at penrith, so please keep that explicitly in mind, coz they don't let you know about it until your first day. you will have to be prepared for exams to get your subjects early on.
in regard to your question, when i did my hast last year, i got really high in english because i wrote a creative piece for a stimulus that was meant for an essay. i used the stimuli as a quote and wrote a comedy piece. i think the main thing that will get you good in english is trying to steer away from what people would typically think to do under the pressure.
math is kinda just whatever tbh. if you're good at math, you will get good on it.
idk what the best provider is however coz personally i didn't study for hast bc i was depressed ab flunking my baulko edutest lol