[*]You don't seem to have enough beam for your aft configuration. Stacking up a two-helo hangar (at least 30' wide), probably at least six feet on either side of it on the flight deck level, and then a boat-width on each side on the next level down (probably at least 12'), and we're up to 66'.[/list]
Just did some checking and 66 feet is not really out of the question. This hull is the same length as the Burkes, and the Burkes have a beam of 66 feet exactly.