Is there a place on this site that has the rules/regulations concerning diving on the treasure fleet, ie: the cabin wreck, or the Atocha, etc... soneone told me that you can dive on these known sites but NOT with a MD...
My advice would be to check in the 'Shipwreck' section of the forum. A lot of the guys that work on these salvage sites post in there and a few that are from the area also.
Remember, the laws are very strict concerning underwater salvage and most of the sites you mention, such as the Atocha, are LEASED and the guys with the lease will probably take a very dim view of you nosing around uninvited. Metal detector would be a definite No-No I would think.