I'm 5'9"–10" (on a good posture day) and I think the 2" is the perfect amount. 4 would feel great for low mode for sure, but I still feel like I've got all the "upper" control with the 2", and still allows me to easily get eyeline with a long post for 6'3"+ people. Was using my Klassen the other day in that scenario and was definitely feeling it more difficult, since the carbon arm natively is lower than the PRO even with the 2" iBaird (but I could be wrong about this, but worth testing).