If it was mine, from what I can see in the photo, I think I would throw a piece of tape on the spine and just hone it with a rolling stroke like I was going along with the smile. When I got down just to a bit nearly past the frown I'd start to go through a progression, sharpening to finishing. Here is the 1961 barber manual PDF from the SRP library which talks about smiling razors and their benefits.
http://straightrazorpalace.com/srpwi...t_-_Honing.pdf