i dont worry about the tips till the very last stage of tillering, they bend alot more once you get it braced at about 6 inches. i still leave 3-4 inches of the tips stiff so i can narrow them later to reduce handshock so keeping them around 3/8 inch thick is good. i suggest if you dont have one make yourself a tillering block by drilling a hole in a 6 inch long block of straight wood to fit a pencil in snugly, just set it against the limb where it bends the most then twist the pencil till its about 1/32 away from touching. run the block up and down the limb and itll mark the stiff spots. i use one of these and it sure beats doing it by eye,lol.