Use the result from step 2 to create a new azimuthal equidistant map, this time centered on the new estimate of the center. Repeat steps 2 and 3 until the location of the center does not change ...

By their calculations, the Mercator projection scores 8.296 and Winkel Tripel does better at 4.563. Their own azimuthal equidistant double-sided projection, meanwhile, scores 0.881.