Love shooting them, love making them. Grinding out #15 right now. Only ones I've "gone wrong" on were my own errors in the building... three of those. Two I rescued and got good bows out of anyway. The third one I just don't understand... I put a tip wedge in backwards and had to cut the limb back 4". Of course, had to do the same for the other limb. I ended up with a 70# bow on a layup designed for 40#. It actually shot for awhile. I still can't understand why it broke 8^)
My first ones had butted joints like you observed. Now I lap joint them real pretty.
As you noted, those narrow limbs are amazingly tough and forgiving. I haven't had one that showed any twist. Just make 'em and shoot 'em.
I've come to think that most of us way over think trying to shoot longbows (real longbows, not the R/D's). I used to try to explain longbow shooting in great detail, but really, they're pretty simple. Now I've boiled it down:
1. Get a longbow.
2. String it up, using traditional fistmele.
3. Find an arrow that flies straight to your eye.
4. Shoot the bow. It'll tell you how it wants to be shot. Listen to it.
5. If after a few months you can't hit with it, accept that you're lacking the longbow gene and go back to a recurve.
Or, as Grandpa used to say: "If at first you don't succeed, try, try again. Then quit. Don't be a damn fool about it."
Sorry... I'm sitting here with my coffee and pipe and feeling a bit whimsical..... But there's more truth in the above than not...