Radiosilence

Hi everybody, here's yet another thread about what classes to take to increase chances of getting into a top 20 program. Im an Australian university student in first year, so have a lot of flexibility w/r/t what courses I can take. I want to have the option open of going to a competitive grad school. 1) any Australians here have success getting into US school from our undergrad? How did you do it/what do you recommend 2) in the bachelors program you can take a second major in a range of subjects - I could do a stream of 6 econometrics courses on top of advanced econ coursework with a smattering of maths, or a stream of maths units and go light on the metrics. Is extra math so important that I should forgo doing emet in favour of it? 3) (very Aus specific) is it worth transferring to a higher ranked school for honours year for better LORs? I'm at a Go8 school that is ranked 5th or so in au for econ. Thanks in advance, I'd love a bit of guidance for now.