cylinder should be good enough. only takes one to stop a rabbit. full choke decimates em with bb loads. the times i use a 12 gage on rabbit i use #7 shot that you typically use on skeet. rabbits are super thin skinned.
but im far far far from a shotgun expert
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...
since you are using large shot you can get away with a open choke. I would use an improved cylinder choke for BB shot. Most of the time BB shot are high brass loads, which means you have more pellets per shell.