10 PSI wont even budge the needle on that thing. Get online and find a 15 PSI gauge or forget it.
You absolutely CANNOT make real and proper assesment/diagnosis of fuel pressure without a gauge that has the correct range.
Look at this one, I have it and it works very well
Super price on KD Tools 2521 at ToolTopia.com
It also doubles as a vacuum gauge, notice 15 Lbs and half the gauge for the sweep....Makes it pretty accurate