I looked into that too, the original FA box will only feed data on port 30002, the RPi is on 30003.
With Port Scanning, the attached is the result (FA use RPi internally as everyone probably knows).
I attempted to use the other mentioned ports with little to no data being fed.
So I’m now guessing, the known aircraft seen visually, may simply not have ads-b fitted or active and I’m showing in VRS what there is to be seen - well, until mandate anyway… Allowing or should I say removing the tick from “Ignore aircraft with no position” does naturally create a greater number of aircraft being displayed as you said. I just feel there must be more not being displayed.
I will try one last experiment, will acquire the latest PiAware file and add Dump 1090, load it on yet another RPi, and simply try that with the ports you mentioned, if for some reason these ports you mention are in fact software blocked like the others is yet to be seen, failing that FA gain yet another receiver feeding them.
Thank you to all that have had input into this trial, greatly appreciated.