It has to be pretty close. It does have a range of adjustment where it's "in spec", but it's pretty small. There's a way to set it with a DVOM (digital volt/ohm meter), but I have no idea what the readings should be.
What he said!
Always crack as many as you can get to, and the first few cranking sessions you had don't mean much if it was getting air. Schraeder valve first until fuel comes out, then prime the injectors.
After that it all depends on the state of your lift pump and IP and starter/batteries. A good IP will prime quickly and a worn out one may never prime with anything but a perfect starting setup.
If you have a manual transmission you can ignore all this and just have a buddy drag you around the block in 2nd gear.