Your setup is cleaner and simpler than mine. I think I couldn't find as complete a selection of fittings to make mine work and had to use uglier messier stuff. Also, I wanted an output on the standalone tank (when all hooked up) rather than on the compressor.
Ok, I got a better idea than using the lever-operated inflator with built-in gauge. Instead, I set my compressor's regulator to the right PSI, connected my clip-on chuck directly with the air hose (no control in between), then just hooked it up and walked away. When I came back, the tire was right where I wanted it to be and I clipped it on to the next tire.
I did have to adjust the regulator a couple times to get just the right pressure (cheap regulator), but once I got it set I could have done all 4 tires without further adjustment (if they all took the same pressure, which on my truck I don't do). It still was way less time/effort than standing there with the lever.
I discovered yesterday that my more portable compressor (looks like an upright vacuum cleaner) pressure regulators were each off by a significant amount. The compressor has separate 40 psi and a 90 psi chuck sockets and a gauge showing pressure before these two pressure reducing valves.
It turns out that the "40" is actually set at 35, and the "90" is at 80. I'll have to open the case halves sometime to re-set those.
I also use a 5 gallon air tank as a reservoir since this "vacuum cleaner" compressor has a tiny .5 gallon capacity. When I need more air flow I wheel out the 2 hp, 220V, 10 gallon compressor.
"Accuracy" is relative. All my bicycle pumps, my digital gauge and the pressure regulator from my bigger compressor are within a few percent of each other. The regulators built into this smaller compressor are the 'outliers' so I doubt them.