first of all, as a knife, I think that this one is beautiful, as is the sheath. I say that as someone who appreciates proportions, design and fit/finish, on an 'artistic' level. And please keep in mind, Magnus, that there are very few knives I've seen come out of your shop that I wasn't blown away by.
However, as someone who throws knives, I have a couple of practical comments/suggestions;
1. That knife is about 4 oz too light for its length.
2. I wonder of the purpose for the wrap progressing onto the blade?
3. I like the balance point of a thrower to be near/just in front of my index finger when holding the handle, so that I don't have too much leverage into the spin and therefore can slow the spin of the knife for a given distance, by pinching the handle between my index finger and thumb upon release. Blade-heavy, in other words, gives more spin control.
4. Aerodynamics and wind resistance are factors in throwing a knife, especially over longer distances, say 3 meters or more, and adding holes doesn't necessarily increase aerodynamics unless 'micro turbulence' is created, (ie; golf ball dimples) and unless you have a way to test for this, I'd forget about the holes all together, unless they're there to add texture to the grip. A well designed thrower sticks well because it doesn't lose too much energy cutting through the air.
5. With your considerable leather working skills, I'd be interested to see you make an inlaid leather handle with texture or perforations, which could be easily replaced if damaged. The issues with wrapping handles is that they come unwrapped when cut, although I noticed that you took that into consideration by keeping the wrap in the middle of the knife.
6. I think that the handle tapers too much at the butt. This makes it difficult to intuitively judge where the center line of the knife is as it's leaving your hand.
7. For a high quality steel, I think that about 54-56 rc is about right.
Lastly, if you would ever like someone to test any of these throwers you are making, let me know. I'm sure I could help you out
