SQ F for sure! I am guessing on DL you cannot take the JFK-SIN Flight? I would route through SFO instead of LAX cause I like the short transit through HKG and the longer transpac. On your flight to BKK, I am pretty sure you can use the SQ F lounge since you paid for an F ticket, and when F Space opens you should be able to get a seat when you show them that you paid for an O class ticket. I have flown between BKK and SIN in F acouple times and it is pretty empty. Although old F seats not sky suites it is still nice, and of course Krug and Dom are served on this two hour flight.