I have built or been involved with over a hundred medium-large strip plank boats from my time selling materials during the home built cat boom times in Aus a few years ago.

Happy to discuss them, but in a nut shell, only a masochist would build this way these days.   Plywood was overtaken by cedar strip for a lot of good reasons and infused foam and glass have taken over from strip for equally good reasons.  Do some reasonable sized, relevant shaped samples before choosing.  

Yesterday I spent a couple of hours laying up a fairing for the mast on Elementarry.  2m/80" long, 750mm/30" wide, 400 double bias with standard grade blown polystyrene core.  Hand laid as the foam would not take vacuum.  Time consuming, sticky, smelly, tedious and no fun at all.  Why anyone hand laminates when they can infuse is a mystery to me.  On the bright side, the resulting panels are pretty good so I would say ploystyrene foam is a usable core for unstressed panels.  I would use it for shelves, verticals on furniture and other unloaded areas, if I did not have to laminate it.  

Also on the bright side, infusion resin is easier to hand laminate with than standard resin as it is thinner and wets out quicker, and lighter as less is used.  It also requires more powder to make filler, which makes it easier to sand.

The samples of the Foamular 700 arrived (Thanks Eric) and I have some 400 Dow foam.  Also got the abrasive string, but it clogs when cutting the foam, so not an alternative to hot wiring unless compressed air can be used to clear it.  I will do the foam tests when Elementarry is sailing.