I've been told that polyesters were reformulated some years ago to make them more enviomentally friendly which started a tendency of boats in salt water
As for covering an old wooden boat and using mechanical fastners I seriously doubt there is much bond at the fastners with polyester. To even get epoxy
to bond to metal takes proper prep. Polyester would have little or no bond to metal fastners. The heavy layup
is what would be the deciding factor in maintaing the apearence of proper adhesion in an older boat.
New construction of a mutli being built in strip plank would not require mat or roving. These materials are way too heavy. Again the binders do not work well with epoxy
. An all glass multi and we are talking multis here not monos would have a composite core
. And again polyester in an all glass boat would be most cost effective. There would probably be an epoxy barrier coat below the waterline.