When I was paying the rent and feeding my family by fixing 18 wheelers, they had many yards of 1/8" OD plastic tubing carrying full air system pressure for transmission shifting and dash gauges. It would be simple to adapt your system pressure gauge down to the 1/8" tubing compression fittings those systems used.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!