Hi,
I also made zero-input noise measurements on the 3458A, full speed with AZ OFF, at NPLC 0.1 and NPLC 1, i.e. 500 and 50 samples/s and NPLC 10, NPLC 100 with AZ ON, each for 1V and 10V so far.
I only collected as many data as needed to get a stable statistics, i.e. 10000 and 1000 samples for NPLC 0.1 and NPLC 1 (20 sec each), and 100 samples for NPLC 10 and 100 (40 and 400 sec, respectively).
Then I made the usual xls population statistics, deriving the average (= DC Offset) and the standard deviation (= RMS Noise w/o DC offset).
The 10V RMS noise fits quite exactly the HP RMS noise specification, 1V is about 3x worse (instead of specified 2x)
I will measure 100mV also, and will try to program for full speed NPLC 0.01, which requires a different output format and special fast data acquisition.
TiN, besides the distribution diagrams, does your script also calculate RMS noise?
Then I would upload the data files to your server.
Frank