Assuming you speak of the front part of the fender,you would have something like a spear point at the tip that would be quickly narrowed to the width of the stripe.I could easily draw this,but do not know how to doit here.The fender tip would be the tip of the "spear".The stripe would then kinda"flow" from this.Iprefer to use a radius on each side,less crude.'Course,never done it myself,but aleays wanted to do that on a bike with painted fenders.Triumph is the brand that did the fender stripe the most,I think.I particularly liked the silver fenders with a blue stripe.about 3/4 of an inch wide,I think it was,on a Bonneville.I believe the stripe ran down the center of the top of the tank,also.Just a nice little touch,kinda thing they were really good at.Sure wish I had one.Bonneville.Friend of mine rode one straight into a ditch at 80.Neck hit the handlebar cross support.Shoulda killed him.Neck looked like a balloon.Blue one.