Re: Boat Slip Size and Questions??
If possiable you do not want to be an any slip in a hurricane! The danger is not the sides of the slip--it is the pilings. The storm surge may lift floating docks over the pilings--fixed docks will damage boats when the boat is well beyond the dock level and level of many pilings and the boat comes down on top of the pilings. I did mini surveys on over 200 boats after Hurricane Ivan, the majority which were holed were from pilings.
You don't want to pay for any more slip than you need--so the length over all of the boat is satisfactory--some places you can get by with 5' less than the LOA. I prefer several feet on each side for maneuvering--but not a really wide slip. There is no advantage to a slip with inches on each side. Be sure and secure the boat with proper spring lines, as well as breast and bow and stern lines.
If you can haul the boat, and get it on a concrete bad with tie downs well above storm surge this is safest. Next is a good hurricane hole, often up rivers well inland, away from other boats, with good holding, wind protection and something on shore to tie onto--like trees or mangroves. Remember the surge in all of these.