Hi Keith..I would brass screw the gunwales and the frames..i would use 18mm bs 1088 plywood from frames this gives you a good width for screwing into the end grain of the plywood, on my canoe i put small doubling pieces ,on the frames this made it very secure.. i have only used copper tacks,the only problem with lashings,they will not sit flat,when you put rubbing strakes on.
the good thing about fitting the deck canvas on last if you have any damage to timber you can remove the deck canvas and get at everything.
- Bent frames are of ash,and they should be flexiable enough to just set them in when you have the rigid frames in place
- kind regards Mike