There is no secret. Basically FI is not releasing their "Intl premium economy" aka saga class availability, there is no need to try, because there are NONE, even for their seasonal ANC-KEF route or new RDU-KEF route. ZERO availability.

For Oceania, FJ is not releasing any premium cabin availability for LAX-NAN and SFO-NAN, and ZERO availability on QF for all cabins, simply NONE.

For Asia, there are couple decent availability on SQ J LAX-NRT at 80k miles one-way in July and August, for other traditionally off-peak season, decent availability on JL in J or even F. KE J availability is almost non-existent. The only Asia route which has AA J availability is DFW-ICN.

For Europe, AA doesn't have any availability unless you book F at T-330 days you might be lucky to get some availability. BA actually has decent availability on LAX-LHR, SFO-LHR, LAS-LHR, MCO-LGW and JFK-LHR routes given frequency and route types (LAS and MCO leisure dominant), but good luck paying $738 surcharge each way. AY and IB has some availability as well even in summer, if you are okay with DE 2-2-2 767 products that's also a choice, but don't even think of EI J availability cuz there is NONE unless you want to pay 280k miles each way. Recently AS released award chart on AT, decent availability, but at what cost? AT only flies to east coast so while AT itself has decent availability, good luck finding availability on AS connecting flight to east coast.

Lastly, Qatar award to middle east, south asia, and Africa, good luck with that..