The 3" and the 1" moment arms give a 3:1 ration between the teetering of the rotor disk and the tipping of the gyro.
The vertical dimensions between the two rod-ends on each rod and the vertical dimension between the two teetering pivots on the rotor hub must always be equal.
Concern:
The maximum torque will be 465 Nm (at 15º). This is 345 lbf-ft and since the moment arm length on the rotorhub 1" long will the force of 4,116 lbf-in be too high for the rods' top bearings, the teetering hinges and perhaps even the rods' lower bearings.
The bearings at both ends of the 'rods' only rotate about one axis therefor they do not have to be conventional rod end bearings.