It is true QF goes out below 100% DFW-SYD given flight length and weight restriction.

I think that means fewer pax in Y - surprised that it's W0 assuming you look ahead.

I imagine ATL-LAX isn't a fun segment, so I do think sticking with ATL-DFW-SYD may be better.

Another input into your decision would be which program you want to credit to, of course. And cost I guess.