Like Carson and Badger, I do it in stages. Draw the whole thing out, and work down the sides leaving it 1/8" or so wider than my lines on each side. Then I work on the belly till it bends a little at floor tiller. I then go back to the sides where I can take off the extra width or leave it if I need it for what ever reason. Sometimes I do need it, due to a knot on the bellies edge or some other somethin' somethin' I missed.