WRT the length of the hose from the plug to gauge, that length is irrelevant if you turn the motor over several times; the idea being to equalize the pressure at the plug end of the hose with the guage end of the hose. Once the hose is pressurized from a couple of revolutions, the guage will be correct.
We’ve had message strings with this discussion before here. Read carefully again the part I wrote about location of the gauge check valve. With the check valve for gauge pressure sensing at the gauge, the hose decompresses totally each time the piston is down far enough to have the ports open, I have a gauge where I can put the gauge itself up to the cylinder without the hose, or put it at the end of the hose with the check valve still at the gauge. Believe me – it makes a big difference where that check valve is on these small cylinders, even spinning the flywheel fast with a socket wrench on an air wrench. Think about it for a while and it will make sense. If the check valve is at the cylinder end of the hose, then what you said makes sense.
Dave
.
.