For a case that costs as much as yours, you can afford good fans. Hydrodynamic bearings or ball bearings. For 120mm fans I use Gentle Typhoons. They are especially good on heatsinks. I use them in my case wherever I must use 120mm fans; I use a pair of PWM San Ace Silents on my heatsink, though.
Wherever you have a 120x120mm window and can fit a 140mm fan with 120mm screw holes, put in the bigger fan. The 140mm fan covers the entire 120x120mm window, where a 120mm fan covers at most 75% of it.
I don't know what fans an FT02B will carry, but the Going Scientific is a decent thread on the subject.