Make sure that you "bench bleed" the master cylinder. It is important.
Some masters for some reason absolutely have to be bench bled. I think that this is one of them?
I suggest "power bleeding" the system with a vacuum pump. They are inexpensive and will help you determine if there is some sort of a leak in one of the hard brake lines.
It will get you probably 95+% there. THEN you probably will need to pump them.
I think that the bleeder valves in the calipers always need to be replaced as part of a major rebuild.
Incidentally, when rebuilding the calipers, partially fill them with brake fluid. It works as a lubricant and reduces the amount of bleeding necessary.
Good luck.