Indeed. What he's done is a coil split, not a coil tap.
Yes, he should maybe be applauded for being a 'tinkerer' '- I'm sure many of us on here are, and more - but throwing in snake-oil blurb about designing that circuit is like saying you've invented the wheel.
If he stuck to the modding/tinkering, fair enough, but this increasing habit of scrawling on instruments with Biro and acrylic paint pens leaves himself open to some well-deserved criticism.