The secret to using my mono-pod, or standing cross sticks, is to make them long enough that you can push them out from vertical towards the target. Then when you put the gun on the cross, and hold the sticks, your body forms the third leg of a triangle( in the case of a mono-pod, your two feet form the other two legs)which creates a very stable platform.
With a three-legged cross stick rest, ( a tri-pod) it stand alone, and you just put the weight of the gun on the cross and shoot. The only problem I have found with tri-pods is finding one that has adjustable legs on it, to deal with uneven ground.
That is why using a Mono-pod is so much easier, and useful. Mine, with the telescoping leg, is very easy to adjust to length as needed on a side hill or slope, where you are either placing the foot of the stick below or above you. You can easily cradle the mono-pod in the web of your fore-hand, while using your knuckles, or your fingers( or wrist) to support the fore-stock of your gun.
The further away the foot of the stick is located from your fore-hand, the more stability you achieve in your hold. Any walking stick, or mono-pod camera support can be used for these purposes.
A walking stick should be at least one foot taller than yourself, so that it can be used without leaning over when going down steep inclines. You want to maintain your center of balance and gravity over your feet, not on the stick.