IF you’re thinking of a xONE6
AND your prime driver is to maximize miles
THEN you need to ensure you make use of the rule exceptions that allow you to visit a continent a second time (see rule 4(e))

Using the exceptions, you can have a total of 9 inter-continental flights.
And you can use just 8 of your allowed 16 segments doing it.
(Used to possible to use only 7 segments – but IRRC the NRT-GRU flight on JL is no more)

Here’s an 8-segment itinerary that consists solely of inter-continental flights
CPT-LHR-SYD-HKG-JFK-EZE-JFK-LHR-DAR
According to MM this is 48,007 miles
The LHR-SYD segment has two inter-continental flights in it
Under the rules – one of the visits to JFK has to be a transit, and the second visit to LHR also has to be a transit

Then look at the best intra-continental flights to gain maximum miles from the 8 remaining segments. There’s a thread on this in this forum.

Edited to add:
A bit of playing around gives this 16-segment itinerary:
cpt-lhr-mct-lhr-syd-hkg-khi-hkg-cmb-hkg-jfk-eze-ccs-scl-lax-lhr-dar
for 74K+ miles