Actually if they are counter-rotating at the same speed then the gyro torques cancel "externally." Whatever structure is holding them in a parallel configuration will experience stresses, though, so that would have to be a strong enough design hence weight etc. I actually "experienced" this recently - my wife bought my daughter a couple of those little spinner thingies people use to just play with or spend nervous energy. I could hold one between my thumb and finger, spin it, and feel the gyro torques. But if I held two and spun them opposite directions (matching speed as best I could) that effect was much diminished.