No saw.  Low-angle block plane with a sharp blade.  And keep the blade sharp (the epoxy and ply glues will dull the blade).

I recently completed an oxford shell that was my first ever boat build. I used a plain old hand saw and used the rasp sold by clc to even it out. The bevels did not meet with an even tight "furniture quality" fit but thicked epoxy filled in the slight gap. The deck will hide these joints from view. The block plane sounds like a good idea.