With one flywheel your contraption stabilizes the camera in two axis out of three, presumably. How about horizontal shake? Tilting the camera is not uncommon, but this will fight that.
I have experience only with Steadycam Merlin*, which does require exact balancing and practice. Also all pendulum stabilizers are hard and heavy to use for any extended time, few minutes start to be painful, unless using a body harness and balanced arm, which cost a lot and have their own problems.
*) which possibly is the best "consumer grade" stabilizer, while not the cheapest.