Mikes,
We have been using the 2/3 (IP3-DANL@1Hz RBW) for dynamic range.
You mentioned a -130 dBm signal with a -20 dBm signal. The noise floor for a -20 dBm signal and reference level would be about -157 dBm/Hz, so I’d say you’d have to have a 100 Hz RBW to clearly see the -130 dBm signal, and you’d have to ensure phase noise wasn’t a limiting factor. At 1 GHz, internal phase noise would not block a -110 dBc signal if you were > 300 Hz from a clean -20 dBm CW blocker. The phase noise should be better than -133 dBc/Hz (>= 10k offset) at 1 GHz, but this goes down 20 dB / decade as you increase frequency.
Also, for 160 MHz patches, you are limited to >= 30 kHz RBW. For lower RBW, 40 MHz patches are used.