>>11324401currently doing gamsat study now and interviewed (unsuccessfully) at USYD in 2019.
it's hard to be really specific because it's ultimately based on your background. if you have no science background, it is a giant pain in the ass whereas a strong science background helps a lot for obvious reasons.
australian medical schools are basically massive cash cows that lure in enormous amounts of foreign students (UQ literally changed from MBBS to MD to please chinese and american students whose countries recognise MD more so than MBBS). This makes it a giant shit of a process for domestic students, where you can have thousands of candidates who all did very well in the exam fight for 60 spots in some instances. If you aren't from smackbang in the middle of a major city, look up the GEMSAS rurality guide to see if you classify as rural. If you do, you can literally get scores of like 58-60 and be accepted into the best schools in australia, versus scores of 70+ for metro students.
the best thing you can do is look at which schools interest you, and see what hoops they want you to jump through. UOM has 2nd year pre-requisites that they're scrapping after this year, Deakin uni has all of this BS bonuses that stack and reward study at their uni as well as financial hardship, work full-time etc. The entire process remains convoluted because you still pay to apply, and if you don't meet their criteria or your score doesn't match up because of stupid bonuses or conditions, you have still paid so they don't give a shit.
as for gamsat, it's fucking hard. people enjoy this weird flex shit where they come out and say it was easy no worries, but it really isn't. I know people who did umat and gamsat, and everyone has said gamsat is much harder. it's also now a giant pain in the ass to prepare for because it's far less content heavy than it used to be in favour of context. that makes it a giant fuck around and can tear strips off 3 months of solid study in 6 hours.