First, with the plane, I’ll take the square section down to approximate depth (for me that’ll be a thin, almost electric style 20mm at the nut and 24mm at the heel), then, using the rasp, I’ll rough in the flattened ‘C’ shape I’m after at the 1st and 12th fret positions. Then, at each side of the neck I’ll mark out the ¼, ½ and ¾ positions around each radius and remove material to join them up using the spokeshave.