I think it all comes down to what you'd enjoy most. I personally did both modern and ancient history and I enjoyed modern a bit more. I found myself to be more keen to study modern than ancient as I generally thought the content was simply more interesting.
Judging by your subjects, you seem...
After trials, it's always good to take a few days off, relax and probably even catch up on some lost sleep. After my trials had finished, I remember taking 4 days off, catching up on lost sleep, gaming and just catching up on movies and tv shows. I believe after taking a break right after...
At one point during the very early stages of the HSC, I had a total of 15 units after picking up both 4U English and history extension - having such an insane amount of units was actually quite benefiting as it allowed me to decide which subjects I enjoyed most and would excel at. Not long...