I've used shooting sticks a lot, both commercial and roll-your-own, with both 2 and 3 legs. Any of them do the job well, if you practice aforehand, a lot. Like most shooting things, you prefer what you're familiar with, so practice counts more than shooting stick style. For standing, I prefer 2 legged sticks, I lean the top slightly out from me and put my left (off) wrist in the fork, then as I pull the rifle back into my shoulder everything is steady up to the limits of my shooting ability.
YMMV
RB
