there's a book by Edwin Monk, "How to build a boat", or a title to
that effect, with a short section describing different kinds of solid
and hollow masts, and the procedure to build and rig them, including
plans for cheap mast clamps and drawings on how to scarf planks together
to glue up the mast. it also gives general formulas for the proportions
of various spars. i'll check at home and post the complete reference.

roberto