Headshot? I've thought about it once, but decided to wait for the broadside. The range was 125 yards, so I thought better of trying it. Now, it the range was under 30, and the deer was totally calm... maybe.
Buckshot is not legal in Iowa, so I have no input other than I know of many in buckshot legal/mandatory areas than have had both very good and very poor performance. I, personally, wouldn't use buckshot unless it was required. Slugs are a much better option when shotgun hunting, IMO.
Mike