The drawing and sail plan in the book don't show the channels in a way they can be measured, so I would suggested running a line from the mast head where the should would lie, to just clear the hammock cranes and measure between the line and the hull to get an idea of the depth of the channels, ie, so the shroud clears the rail. Compare that to what you have for Constitution and you should sailing in safe waters.
Check at each shroud because the channel may be narrower at one end than the other because the angle of the shrouds changes slightly.
