Wasn't it so that the other systems were always visible when looking up on the original site?
If so then I have a Theory that all the unknown sites always should be able to see the original one. From there you can further narrow down the possible locations.
On a other not I'm mostly searching in the system IC Sector GW-V B2-4.
Were I think there are a few planets that are most likely to hold a ruin.
First a Screenshot of the entire system map to help others probably save some time with searching for possible planets.( i could have missed some with my basic Discovery scanner)
Take not that the fourth star is +- 45000LS away from the one you arrive at and only has one good looking land-able planet which is probably disqualified for being to cold.
The most likely candidate is IC Sector GW-V B2-4 A-1. It has 315K temperature.
The others that could also possibly have one, if temperature wasn't as important as having a orbiting planetary body. Then possibly IC Sector GW-V B2-4 A 3(207k temperature), IC Sector GW-V B2-4 A 4(207k temperature), IC Sector GW-V B2-4 B 1(207k temperature) and IC Sector GW-V B2-4 D 4A(51k temperature). B-1 and D-4 also score good in the screenshot category.
Here are some screenshots of D4. This planet kinda makes me sing Uranium Fever.
I hope this information can help a bit to solving this puzzle.