I'm flying LAS-LAX-SYD in January and the two segments will be on separate tickets on UA. What do you recommend as a minimum connection time between those flights? UA839 LAX-SYD departs at 22.30, so would it be OK to arrive on UA from LAS at 21.13 or am I pushing it. I hope that my lugguage can be checked through at LAS all the way to SYD even though flights are not on the same ticket, couldn't it?

I was going to book the domestic US flight on ual.com. Can I add the booking reference of my international flight on UA to this reservation later on? Would UA take notice of this in case they change the flight time on my LAX-SYD flight or would I have to buy a new ticket if I missed my onwards flight due to any changes? Don't know whether they need to do anything if booking is not on same ticket, but there is no other way to add the intra-US flights to my original booking. Any help appreciated.