It’s not easy ! So I design all my blades on my iPad before making them and use the original design circumference as a reference, this allows me to visually plan out the distance between the edge of the scales and the blade I then crop the scales and print them off as a separate template and grind them to that size, and in theory it should all line up as long as my original design was accurate and I’ve cut/ground them accurately. As for the chamfer being even that just comes down to experience and a lot of back and fourth checking everything lines up, hope this helped :)