As mentioned, the TG lounges are utilised by QR; The bigger lounge at D pier seems the best bet though the lounge at E isn't too bad & overlooks the usual QR departure gates in E pier.
As for the OW lounges (when I departed on a Monday evening); The CX lounge seemed a bit on the small side for my liking. The QF lounge was a good size & had the best F&B offerings but was also the busiest. The BA lounge had a notice stating only open in the morning.
I settled on the Japan airlines lounge which opened at 6pm; medium sized with an OK selection of F&B. The big attraction for me was it was very quiet, Mrs IM & I were the only people in there for about 1½ hours.