Past threads were based on the 20 segment limit, so not really relevant. Many of the long opportunistic flights are seasonal, so it depends on your travel dates. In general pick long AA flights in the US (which book into A); avoid the J-only flights (e.g. Carribean services on AA). DFW-ANC is good, as is LAX-SJU. JL has some good legs ex-NRT (eg NRT-DEL) but many do not have F (J only). BA LHR-DXB etc. is of course a must. But are you really so hard up for points that you need to squeeze the itin this much? Better to pick nice routings to cities you want to visit.