This is really a hack for people who already have a helmet and are working on the next one. If you already have a helmet and are pleased with the way the ears look (even if there is still a gap), your next set of ears can come ridiculously close to perfect!
1. Tear a wide sheet of aluminum foil about square. Fold it several times (for rigidity) until it is a little larger than an ear cover with good margins.
2. Press the foil tightly around the ear cover on the existing helmet. Capture