Your best bet for slugs through a full choke barrel is to use the rifled slug with the smallest diameter. I read somewhere that Remington sluggers were the smallest for 12 ga. rifled slugs.

Buckshot, if legal where you hunt can work fine, just pattern the gun and limit your range so you get at least 50% pattern within say a 10" circle.

If you get acceptable accuracy with a slug out to 50 yds, I'g go with a slug.