Do you shoot w/ the camera straight up and down or slightly forward at an angle up to 45 degrees?  There is no vertical gimbal motor to control the sudden motions if it's straight up and down so I think a slight angle is important to absorb the impacts?

Is the real professional way to use your knees as the gimbal?

From what I have learned from scouring the interwebs, minimizing the Z Axis up and down motion is the challenge with all handheld stabilizers.

A professional Steadicam rig will have an ARM and vest that helps isolate the user's up and down motion from affecting the rig.

Since we don't have a mechanical arm, our arms will have to be supple enough to absorb and minimize the up and down motion.
Everyone recommends:
Use a wide angle lens
Practice walking with cup of coffee in front of you.
Do the Groucho Marx duck walk to minimize bouncing.
Use a skateboard, one wheel or wheel chair.
Add stabilization in editing. (This is what I do for less than perfect operation)

Or, you can consider something like this: https://tiffen.com/products/steadicam-steadimate-s   that works in conjunction with the Ronin-S.