My school has a countdown timer on the screen for exams to tell us how much time we have left. I think it's definitely something you'll have to ask your school about/if you want to bring for trials. However, I'm not sure if you can bring anything in to the room for the HSC (besides pencil cases).
By pencil cases I assume you mean clear unlabelled plastic sleeves / zip lock bags
. You can also bring water, tissues and chewing gum (it actually helps you think, just don't chew like a cow and you'll be fine
)
You can bring in a wristwatch as long as you place it on the top right hand corner of the writing desk can you not? Smart watches or programmable watches are obviously not allowed but here's an idea (don't blame me if it doesn't work haven't tried it just thought of it now!)
Set your watch to be at 12 o'clock when the exam begins. Say its a three hour exam and its currently 2:20pm you can easily see 2hrs 20min has elapsed. Just take into account reading time and what not.
Does this make sense? Is it a better alternative? Let me know if you use it and if it works!
Also, there are external BOSTES people as the supervisors, not your teachers just letting you know