... And the fan fixing screws on my 2009 MBP were *smaller* that the size implied by the tool requirements for this project. I initially tried a Phillips 00 screwdriver but it nearly stripped the screw head. It was necessary to switch to a Phillips 000 bit to actually get two of the screws to move.
Taking those hinge screws out can be difficult (they are fat, and they resist turning). In my first attempt I destroyed the Torx screwdriver bit (soft metal, I discovered, so the bit twisted into a corkscrew before it snapped off). After buying the ifixit screwdriver set I found that the driver bits were tough enough, but the screws still would not budge! So, I used a small mole-grip wrench to hold the metal part of the screwdriver, and GENTLY turned until I felt the screw give way with a click. Luckily, the threads did not strip. However, if you find that even with that extra torque from the wrench, it is still resisting in a big way, go one more step and try a very tiny drop of thread-loosening fluid on it. (That last suggestion, however, is risky, so be careful.... do not let any fluid get anywhere except the screw, and then give it time to work).