That curved grind line is a new acquisition for me. I decided this year to learn how to do it. I am still learning (story of my life!) and think I have the basic technique down. I hang the belt about 1/4 inch over the platen when doing the plunge cut, and do it with a sweeping motion. Sometimes it works out better than others. This one was OK.
Sometimes, it takes me almost as long to make a sheath as it does to make a knife. My sheaths improved mostly when I stopped looking at it as a burden that had to be done, and started looking at it as just another step to producing a finished knife. I rarely produce a knife without a sheath, and when I do, they are kitchen knives.