AA RTW desk has always been able to release A/D inventory on request for Emeralds, so the lack of inventory is not really a problem as long as lots of J seats (and typically there are to/from NRT). In the worst case NRT-SJC is always available these days.

Presuming the mileage on the circle fare is calculated the standard way, you could go bne-hkg-phl-lax-bne which is 21981 miles (actual travel is of course hkg-jfk-rdu-phl-...-lax- ).

You could even route via MIA, e.g. hkg-jfk-mia-phl-mia-jfk-lax (jfk-mia is 60 SCs). Even better, so is phl-mia (but bwi-mia is only 30 SC). So you can get an extra 240 SCs for jfk-mia-phl-mia-jfk (all this presumes that circle fare counts mileage between stopovers and not including transits).