Orphen89 said:
When you say it depends on what "individual subjects you do and how they are timetabled," do you mean that certain subjects have particular times during the week which cannot be changed?
Individual units of study would normally have one set of lectures which can't be changed, or possibly two or three sets to choose from in more popular units, as well as multiple tutorials at various times, which you can choose from. If, say, a history subject you're doing only offers tutes on Tuesdays, and an English subject you're also doing has lectures on Mondays and Wednesdays, then you're stuck with that and won't be able to compress your timetable into two days.
Orphen89 said:
And, when you say that the process at some unis can be difficult, what kind of difficulties do you mean?
I was basically referring to Usyd, which has an antiquated online timetable-changing system where you have to convince it to allocate you to the tutes you want. As far as I know all other unis let you choose any tute that has vacancies.
Orphen89 said:
And finally, if you do change your uni timetable to fit into 2 days, would teachers/lecturers take you during this time, or can you only go to lectures when they are available?
You can only go to lectures and tutes as the uni schedules them (see above). If the uni's options don't suit you, there's not that much you can do about it.
Edit: and melsc is right, it's unlikely that you'll end up with two days even in a course with low contact hours.