I hunt from a ground blind...., I also teach hunter safety, and since the vaaast majority of "hunting" injuries come from folks getting in or getting out of tree stands..., Dave has decided that to avoid a tree-stand-accident, Dave don't climb no trees. :haha:
Now I make my blinds at trees with cross branches that allow me to have a shooting rest, either while standing or while seated. Mostly standing, and otherwise when I move through the woods I stop at a tree that I can use with my forward hand/arm to help steady the rifle. I have only made one true "offhand" shot on a deer, at that was close at 30 yards.
So..., it's good you are thinking of increasing your steadiness. I would say make your own single stick. The store bought stuff is made one size fits all..., which means one side Sorta fits all.
The best ones that I have seen are used as walking sticks. The user had a cord/rope arrangement that he could moved up and down the stick with a loop. At the top it helped him keep hold of the stick, and worked when shooting while standing..., when moved down the shaft of the stick it worked when he was sitting.
LD