Someone should check my maths, but if the goal is to maximize TPs then the QR option is probably best (140+160 ow). A BA routing would produce 40+240 ow unless you find a way to break the journey onto a different flight number for the SIN-SYD leg. If you can get a QF codeshare on EK the numbers should work out the same as QR. CX will yield 140+140 ow.