The childish building cities on the flat playroom floor rears its head with the great U.S. myth that only rigidly grid based cities are beautiful cities following closely behind. Please forget the rigid grid of roads as a requirement of the "city beautiful" !! The actual islands of the Caribbean are of two basic types, volcanic with high elevations and drown land crusts with moderate to low elevations. So picking one elevation for your "tournament settings" is rather arbitrary. For elevation
, I suggest the fifth point from either the top or bottom since that is as close to the midpoint as you can come. That is the recognize that very flat and very high islands are also realistic Caribbean islands. Very flat islands have generous, wide beaches; the high islands have few, small beaches but very good fishing grounds.