I like answering more technical questions. Hey City, I'm not sure how familiar you are with Tart Optical frames but I've come to understand that a person can wear say 48-20 in modern frames like Mikli for e.g., 52-17 in vintage aviators and a smaller size in browline/thicker vintage frames? How would one be able to distinguish given that vintage frames run smaller? Also is Shady Character a separate company or is it a model made by Tart? On edit - I've come across this link however I'm still baffled what size would be appropriate for a Tart/Shuron frame. http://optometristattic.com/Measure.htm I've used this - http://tartoptical.com/images/fitting.pdf - as well but don't think a 46 would work for me. Need some help with this.