You will have a hard time redeeming on SQ in business class or first class because they restrict mileage redeptions for most *A partner airlines including UA.
You best bang for the point redemptions would be business class or first class on *A partners like Asiana or ANA or Thai. Business would be 120k each and first would be 140k each.
There is normally pretty good availability far out (> 8 months) or within 2 weeks of departure. Hoilday periods are an exception to this rule.
Depending on how much time you have you can do a stopover on round trip tickets. Think LAX to Beijing (stopover) to Bangkok (destination.)
Or if you enjoy flying as much as the destination you can string together a bunch of flights like LAX-JFK-FRA-PEK-BKK and then BKK-HKG-ICN-NRT-LAX.
SunLover