You guys are over thinking this. If you are only going to shoot reloads and the die you are using is the one you are going to reload with then set your die and resize your brass. Then put your piece of tape on the base of the brass and set your head space. You now have your head space set to 1-2 thousandths clearance (depends on thickness of tape) for your reloads.
If this is not the die you will be using wait for the gauge.


Zero, Factory ammo will vary from lot to lot so you could set with factory ammo and not be able to chamber the next box you buy. Factory ammo is notorious for excess head space.