The circuit works and I have built two of them but it suffers from a transient voltage issue on startup. You need to read the threads about it over at their forums because the project you linked to suffers from underrated components and has been reported to fail. See my posts about adding Q1 with its voltage divider back in too, it solves a shutdown transient. You'd hook the voltmeter across the output and the ammeter across R7 if you want to measure the load current or from ground to pin 3 if you want to translate the 0-1.41V to 0-3A through a voltmeter circuit to show the current limit setting. The latter is how I'm going to do it. If you do build one, don't hook it up to anything sensitive before turning the power on. At 30V you'll see around a 6V spike.