High School English teacher here.
Pupils do a Scottish Set Text (a play, novel, 4 short stories or 6 poems). This is worth 20% and the SQA produces a list which the teacher picks from.
They then do a Critical Essay, also 20%, on a text in a different genre. Most schools choose poetry for Scottish Text, leaving novels, short stories, plays and non-fiction texts for the essay.
In my department (PT) I encourage teachers to choose texts that suit them, and importantly, their pupils.
"Shooting an Elephant" is short prose non-fiction and very straightforward which means pupils do well. It will not stretch the most able. Nor will "A Hanging" another popular choice also by Orwell. But lots of pupils do them.
We always do a meaty text. Things like, "Gatsby" or "Streetcar Named Desire" or a Shakespeare play or a modern novel like "A Handmaid's Tale". Prose non-fiction, as above, is there just in case or to support weaker pupils.
My advice would be to focus on reading anything and everything over the summer. Newspaper articles are the basis of 30% in the Close Reading assessment and if you can read, discuss and help with vocabulary that is often the most useful thing. Guardian, Scotsman, Times etc. Not tabloids.
Happy to help if I can with other questions.