If it goes down, build ya another.  Fretts , dont know, tiller looks pretty good to me. Maybe longer and wider design would help.
Also do you use a string nock? I still use one squared to the handle rest or top of wrap.  I know not primitive , but hey this bowmaking is individual thing. In the last pic looks like you holding string a little high of square, that may alter the appearence of the tiller some. 
mack