I am planning to upgrade a JFK-LAX-SYD paid ticket (with JFK-LAX in C+ (W fare code) and LAX-SYD in PS (G fare code)) to Delta One for a trip in 2021. My question: to upgrade to Delta One, will I be using 45k SkyMiles for the entire outbound segment (JFK-LAX-SYD), or just over the water leg (LAX-SYD)? If latter, then should I be using a RUC or more SkyMiles for the JFK-LAX domestic leg upgrade?
I am yet to call the DL DM desk...but thought I'd ask here first. Thanks.