The spar bench has been topped with 16' of 3/8" plywood. This is adequate for the booms, yard and mizzen mast. An additional 4' of ply will be added before I build the main mast.
Dry fitting the top, bottom, plugs and spacers for the boom. Once I'm satisfied with the fit, I'll glue this assembly together and prepare the 9mm plywood sides (need to butt join the ply to the needed length).