Graham,
Interesting way of doing it! As I said, "everybody has their own way of doing things and most of them work". I have never considered splitting the hull longitudinally, but I can see the logic behind it. Food for thought......
Simon,
Good luck with the build - keep us posted and take some photos. With my hulls, once they are planked, I give the INSIDE a thick coat of two-part resin - I use Z-poxy,which is model aircraft stuff - and use sanding sealer on the outside, followed by primer, rubbing, more primer,more rubbing and so on.