Both can effect each other, as the clutching is calibrated to appropriately load the motor upon acceleration, and changing the gearing can change the amount of torque seen by the primary clutch.
Rule of thumb, lower gearing means the 2ndary can shift easier, thus allowing for more helix angle.
Unless grass dragging though, the RX is not a sled that likes to be geared down.
The stock clutching is very conservative.