t's not much harder, honestly. Here's the maths: in VCE your aggregate is your top 4 scaled scores (including English) plus 10% of your 5th and 6th. So a 6th subject only adds 10% of its scaled score — if it's a weaker subject it barely moves the needle. Plenty of people get 99+ with 5 subjects.
The real difference with 5 is there's less room for a bad day: every subject counts, and you can't drop your weakest. Tips that matter most: lock in English (it's compulsory in the top 4, so it carries the most weight), and be consistent across all 5 rather than gambling on one standout subject.
If you want to see the actual numbers, try modelling it: plug your expected study scores for 5 subjects vs 6 into a calculator and compare. I made a free one covering all states with no sign-up: — run a few scenarios (e.g. what happens if one subject drops 5 points) and you'll see exactly how much buffer the 6th subject gives you.
Good luck, 94-96 is very doable with 5!