Try to get the SQ BP for CGK-SIN issued before you get to CGK (ie whereever CX777 originates) if you can. If you already have BP then 1:20 is easy connection (assuming no checked luggage) - some of us have done turnarounds of 1:00 with no problems. If have checked luggage then it will be tight as need to clear immigration which can take a while.

Sometimes will get carry-on screened by the escalator, sometimes not.

Note will need to pay IRD 100,000 departure tax at the gate. Can pay in US$ (probably $10) or SIN$ (currently $20) also - notes only, no change given.

As for the flight. It is okay. Comfortable seat. No avod, only wisemen 2000. Nice light meal and free flowing drinks (krug or dom for champagne). Likely to be fairly empty in F.