You dont have to do both pictures, I believe the picture of the top of the board will 12v the GPU side, and the botton will 12V the CPU side of the fan. If you want both fans running on 12V then you need to do both. In the second picture there is a red jumper drawn in that is hard to see, so dont forget that.
probably the coolest thing to do is use 2 dpst switches, one for each fan that allows normall operation, and 12V operation.
I havnt done 12V of fans this way, I have only hard wired them to the 12V source. If all you wanted was 12V all the time than hard wiring it is much easier and safer.