The two issues I identified with these cheap meters in my reply#36 were their burden voltage, and (on some meters) that you couldn't dial-down your PS below a minimum voltage (4.5V) without starving the meter for power. Fortunately, the burden voltage from the meters built-in (low-side) shunt can be removed by attaching the wiper and lower fixed contact of (10T) pot R37 to point B (vs. A) in the attached diagram (from
rolycats link). And by providing the meter with its own FULLY ISOLATED supply, it will happily read 0V with R37 fully CCW.
Having two shunts in the circuit does introduce another voltage drop (probably by a few 100mAs) between unregulated to regulated sides, however, I think the simplicity of the meter installation makes up for that; ie. NOT having to configure the meter to use your existing shunt (R2), choosing a full-scale Vref, calculating dividers, and re-calibrating. And the bonus of eliminating R11, R12, R18, and R17. UNFORTUNATELY, by using this meter (with built-in shunt) you won't be able to set/view your current setting by pushing momentary SW1A. Instead, you'll have to short the outputs while adjusting R19.
These cheap Chinese meters are not based on the custom logic ICL7107 ADC but instead on a cheap ($1)
STM8 MCU with 10bit ADC. It probably uses
oversampling to get 4 extra bits to achieve 10,000 counts (at 2 Hz refresh).