[Liam]

CSM stands for "chopped strand mat"
As far as one layer,1708 is actually 2 layers it is one layer of 45 degree woven fabric with a layer of CSM stiched to the back of it. Providing you don't use polyester resin 1708 is extremely strong and waterproof.
The deck will be screwed to the stringers and bulkheads,there will also be a layer of thickened resin on top of the stringers/bulkheads to allow for any undulations. The stringers will be screwed at the overlap permanently,when i glued the two layers of stringer together i put resin between the two and screwed and clamped them until the resin had set then removed the screws.

Glass tape saves cutting as you mentioned and is used for tabbing in.

Your stringers are taller because you have a later boat that has a self bailing deck ,the deck was raised to be above the water line and they increased the cap height to allow for the loss in freeboard.