Thanks for the help with the 2 stopover piece. I must have (repeatedly) misread that portion of the rules.

Given that, I think we are going to try:

nrt-pek, sin-per-drw-syd-akl-scl-ipc-xscl-lim-gru, eze-lhr-cai-lhr-nbo, jnb-xhkg-del-nrt

This uses all 20 and comes in at about 51800 miles.