If booked on QF107 or QF108 between SYD and JFK the distance employed shall be the GC distance between SYD and JFK. GCM
indicates 9950mi (Qantas dock you 3 miles for some reason).
There is one major problem in this case, the distance between your YVR and JFK must be included in the distance calculation as it's considered a "Surface Segment" (to complete the "circle").
The excerpt from the rules in post #2 refers to "origin-destination surface segments".
Clause I of the xCIRnn rules indicates the following: (My bolding)
Surface travel and use of other carriers between intermediate points along the circle which are not operated by AA/BA/CX/JC/JL/JO/KA/ LA/LP/NU/QF/XL/4M is permitted at the passenger's expense and must be ticketed separately. Mileage must be included in the MPM calculation.