my best advice is to watch some video's on cutting dovetails and ripping with a hand saw, than go and practice those operations a little bit.
its not the same as cutting a splice on the uneven surface of a bow stave but it gets you some practice and confidence with a handsaw and the techniques used with it.
too i would recommend starting the cut with a backsaw if you have one even if it cant go the full depth of cut, once it bottoms out switch to a handsaw.