I dont worry about overpenetration as I have caused all the nearby neighboors to move already.
Would choose M1 Super90 and 1911 as back up.
Will shoot 000 OR Brenneke 600grain hard alloy slugs. Dont want no one hiding behind sofas,walls, or cast iron sinks thinking they are safe.
Have five shot 45colt with 300gr hard cast at around 1600 if the above fail.