You don't need to loosen the lines. It will indeed bleed the injector lines out with ease with all the fittings tight.
You are right, the system is not self bleeding. That is why you use air pressure to push the air out of the lines before the injection pump. Beyond the injection pump, the only way to get the air out of the injector lines is by cranking the engine. The lines from the injection pump are fairly short and it doesn't take that much cranking to remove the air from them. You do not need to loosen the lines to bleed the air. Even if you do, there will still be some air left at the end of the injector lines and how do you get that out? By cranking, of course...
Most of the time when people do loosen the injector lines, it is to see if they are done bleeding the system. They know that once there is fuel at the injectors, they have completed the bleed procedure.
When the bleed procedure is performed correctly, you will find that you can simply crank the engine a couple times and it will start.
If you are doing things correctly using the air pressure method to bleed the lines, there is usually no need for a battery charger since it takes very little cranking to get the fuel through the injection pump and to the injectors. If you messed up somewhere along the way (it happens to all of us) then you have to crank long enough to draw the fuel a long way and that will kill the batteries and starter. Usually it only takes one or two 15 second cranking sessions before the engine starts if you have done things properly.