Really make sure you focus on maintaining your posture - it's very easy to think you should bend your knees more or operate in a crouched position or lean forward, in order to try to get the camera lower - whether consciously or subconsciously.
If you find you feel like your fighting the sled, take a second check your posture, let go of the gimbal and arm - is the sled shooting toward or away from you? side to side? If so take a moment to regain proper balance, or adjust your vest, etc.
fighting the sled is always going to make any operating (high or low) a lot more exhausting than it needs to be. Just remember, you can always take a moment to find if you are fighting the sled and in it what ways, adjust and proceed.
Smooth sailin.