Airlines/Pro Tec Bari case as carry-on?

I'm traveling to Australia this fall, and I'm wondering what experiences people have had taking their Bari sax onboard airlines as a carry-on (I'm currently using the Pro Tec contoured case). I've only had to travel with tenor/alto before, so this is new territitory.
Obviously, I'm very concerned about showing up with my horn and having to check it underneath. I can borrow a huge flight case, but then I have to travel in-country with it as well. The other possibility is having a horn provided there, but I'll still need to take it with us on local flights.
Are there different size/policy regulations for international and local Australian flights (I believe all our travel is on Quantas)? Any way to get clearance in advance?
Any help/thoughts would be appreciated.

-Jim