|seconds. There's also the option of jumpering the FP in hatch area using a battery.
Yes, plain petroleum jelly works just fine for installing the injectors in the rail. It disolves in gasoline too. I like it better than using motor oil, a little less messy and stays put at room temperature. Works good for installing hoses onto fittings too.
FWIW - when working on my bench with a rail I've used a garden pump sprayer tank, pressure guage and hose adapter to pressurize with air. Let things set for 5 mins or so and see if pressure remains steady.