The JFET matcher is an ancient and established piece of tech around here lol, this site has a layout for one here. The one you linked is slightly different, but I (and many others) can vouch for the one I linked. I built this matcher and a germanium transistor tester into one of those handheld enclosures with a self-contained voltmeter and it's one of my most useful tools.
I am with Silver Blues in that the updated Runoffgroove JFET Matcher is a simpler, well-tested, and reliable circuit. Most JFET spec ranges you'll find in forum posts or build docs are measured using this circuit.
Yeah I've been using the greatly improved one for stuff where you don't need all 3 readings, and more of just a match. I have a build that needs pretty specific device ranges and the schematic I linked was specified as the best way to get the right range jfets