Three? Sorry. You mean two for the 2X 290x with h75, h90 for the cpu.
So you can put the radiator (CPU) on the top, two radiators (gpu) inside the case where is in the HDD cage area. Like in the link, it may work. http://www.hardware-360.com/wp-content/uploads/2013/12/241.jpg
Because it is from the review. They use the same case but the GPU is gtx780ti, which is shorter than the 290x. http://hardware-360.com/nzxt-kraken-g10-liquid-cooled-gpu-mounting-bracket-review/4/
I don't know your thermaltake armor that is the bottom PSU mounted or the top mounted. If it is the bottom mounted you can try this way to see you work it out or not.