Thanks to the fantastic work of Lauka and everyone on the forums, we now have a specially tailored firmware for tricopters dubbed TriFlight!
The new firmware vastly improves the flight performance of the tricopter as it features a ton of optimisation specifically tailored for tricopters. Among other things it features a custom in-flight adjustment for the thrust to torque factor of the powertrain as well as a equal yaw rate algorithm to get the same yaw speed in both directions.
If you want to join the development, there is a +40 page forum post where this firmware was born and polished by our fantastic forum members. By tricopter pilots for tricopter pilots. Together we are strong!
If you want to print or cut your own Servo Setup Tool you can download the STL and SVG file here. Be aware that I have not tested if this file prints correctly. The file was designed by trial and error on my laser cutter. The file might need adjusting to get perfect 40° deflection.