Isn't that data already in Ross / EDDB for the most part? Reading it from there sounds like a better idea than messing around with fake journal entries.
I had a conversation with Anthor and others in the EDCD Discord about this - the consensus is that it'd be better for everyone to get that data from the game itself - see my edit above for details - and that way accuracy of EDSM, EDDB etc. is guaranteed, as there have been instances of someone apparently deliberately inputting false data into one or two 3rd party sites.