This thread is a few months old now but I had a similar question and I figured it would probably be best to ask it here, sorry to bump it.
I too am looking for the best lounge as I have several hours to spare in the middle of the night and don't feel like going into town or hanging out at the transit hotel, but I simply cannot make sense of the lounge requirements (I guess my confusion comes from Silk Air's relationship with *A and SQ).
I am flying out of SIN on a Silk Air (SQ coded) flight in Business Class.
It's a *A award ticket issued by UA (and I will arrive in SIN via TK and SQ if that matters).
Any input is very much appreciated, thanks!