i say make those tips work, tiller very slow. you should get a nice half circle(minus the tips of course). i usually take a protractor and hold it up to my eye and make the bow match the shape. but make sure the tips bend the same amount on both sides, its a tricky balancing act, but im sure you can pull off a 24" draw. which is a normal west coast draw length.
im assuming the arrow is passing threw at center?
(edit***) and it looks like you took the sapwood off, Good job! you did your research
-Pinecone