Won’t work. Block is just a manifold with no orifice between the two pressure gauges, and both gauges (different ranges) effectivly measuring the same pressure. Poor quality regulator also which doesn’t maintain manifold pressure under flow well. Any reading you get when connected to a cylinder is due mainly to the pressure drop in your connecting air hose and irrespective of the actual air loss. I can add an orifice and modify it into a working device, but if you don’t have the ability to modify it the readings it will give are pointless.