I have to add something, I have done what you are doing and while you may know how to go about it I'm going to add this anyway. With a root and tip profile pattern your good to go but a flat bar only sands flat spots and are only good to rough in the shape, Then I use a shorter bar (6") and mark radial lines 3 different places and sand the rest radially gradually moving down the foil. you will see the lines start to go away and when they are all gone you are nearly done. You can find the high spots with a straight edge mark them and finish it up with 220 grit on the long bar sanding in the same manner. Heck you probably got it done by now, maybe someone will get something from this.
Leroy