I would say go for it. QF have two flights to LAX, and one to SFO (ending in may).

Weight restrictions can still, but far less regularly, occur ex-LAX. Out of Aust. is usually fine however.

QF and JQ also operate to HNL, possibly another backup for you?

Just beware of school holidays, I am not sure about the exact dates in SYD this year, but it is always busier.