Optimal Recording Levels

Thank you, Laszlo … let me see if I have this straight.

1) If a pad is off, then 0db on the meter is 8.2dBu, iimplying that -3db on the meter is 5.2dBu, and -30db on the meter is -21.8dBu. Right?

2) If a pad is on, then 0db on the meter is 20dbu, -3db is 17dBu, and -30db is -10dBu. Right?

3) Is it true that with the pad on, the meter shows the input signal and that the actual signal being recorded is reduced by 10dBu? For example, if the pad is on and the meter reads -3db, does that mean that the input signal is 17dBu but the recorded signal is 7dBu?

4) Most Important Question – What is the “optimal” dBu for the recorded signal ( not the input signal)?