I am also new to leatherwork, and there is (So far) the inevitable screw up that happens. I have found that in most cases, leather is a very forgiving medium and I have not yet had to throw away anything, although my first guitar strap might get re-purposed as a wall hanging art piece :/
Anyway, I have recently made my first knife sheath as well. And, it fit your knife perfectly! My friends hunting knife is the same as yours and we were both shocked at how well it fit. It was a complete fluke, but if you want a pattern, I could draw one up for you. Here is a picture of the sheath to see if you like the design.
If you truly can't make one to your satisfaction, mine is available if you want it! Mike
PS, look at the stitching on the back. It's not pretty either!