Am I a competitive applicant internationally?

My undergrad university is a pretty no-name institution with small class sizes and not very competitive peers, so I have no way of really knowing what I’m up against on the ‘world stage’. I’m in Australia at the moment, and looking at a few PhD programs around Aus and Europe in astrophysics. I don’t really know what tier I should be aiming for though. My stats are good, but as to whether they’re good enough for the top places, I can’t say. I’d definitely need to apply for some of the really competitive scholarships to afford the move though, and that sets the bar high.

For the academic side of things:

GPA: 7.0/7.0
1 first-author publication from first year, probably two more submitted by the time I apply anywhere
Prizes each year for coursework
Research experience all through undergrad with my home university, and a summer spent with the CSIRO
A few international conferences (1 poster and 2 talks)
Expecting first-class honours as long as I don’t bomb my last exam, and then the university medal from that

For the ECs (for scholarships):

Founded a tutorial system at my university
Lecture series each year for National Science Week
Science in the Pub talks
Public talks for astronomy festivals/clubs
School tours
Heap of hobby stuff for martial arts and literature

My honours supervisors are both Gates-Cambridge recipients (and have worked at those kinds of university) and they’ve said they’ll help me tailor my applications for that level of program/scholarship, but neither are the type of person to ever give praise for anything so I can’t gauge what I’m up against. I’ll never get anything other than criticism out of them.

I figure the GPA is expected of an applicant and most will have at least one publication. I don’t know how much my supervisors’ connections to the faculty in these places will matter, since they still publish with people who work there. It’s a bit too early for me to be scoping out specific projects, but that’ll undoubtedly inform where I apply to as well.

Connections are very useful. A personal recommendation from someone they trust is valuable. Your GPA is fine and you have good research experience. Just make sure that your GRE scores are strong and you should be fine. Look for programs which specialize in the kinds of research you are interested in and then ask your research mentors to help you choose where to apply.