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
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"I crapped my pants to avoid the draft!!" -Ted Nugent
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.