Hello! I am going to be traveling from the U.S. to Sydney on United. I want to connect to a Qantas flight on to Cairns. A few questions:
1. Can I check my bags directly through to Cairns?
2. How much time should I allow in Sydney?
3. If there are delays will Qantas work with me to get me on a later flight?
4. Are carry-on policies much different from the US carriers? I see they limit you to 15lbs for a carry-on. Do they weigh these or is this more of a suggestion.

Thanks for the info!