I have one but have not used it. I have a Hawes Western Marshall to practice on when I get caught up. I just received a five degree forcing cone cutter from Pacific alsomafter a seven month wait.
The Hawes is inaccurate presumably because of an oversize forcing cone. I will run some test targets first with 3.5 gr of Bulls eye so I can see if we get an improvement after a one turn setback.
The tool looks very well made, and has reasonably complete instructions. I can imagine that there might be considerable "feel" developed as you use it. I don't yet have a piloted square facing cutter in .357 to set the gap. Quite a few other projects ahead of that one unfortunately.