You can make assumptions and educated guesses though, so 17ly or less is a good place to start.Sadly there is no way to even guess the range - so really, just go for a number you like the sound of and work on that
The 7ly limit is a myth (it's not a limit present in ED Lore, it's based solely on Elite). We have zero info on "old" hyperdrive jump ranges as relating to ED Lore other than the FSD (from contextual assumption) jumps further than the Quirium drive. Thatchinho did a pretty cool experiment and proved that "in the past" Hyperdrive ranges did exceed 7ly even in the earliest days of hyperdrive travel: https://forums.frontier.co.uk/showthread.php/380519-Guardians-Discussions?p=6159264&viewfull=1#post6159264
There's also no telling what modifications, upgrades or experimental drive systems JJ was using - we know that the Pleiades was well outside human space, so it's possible that he was chosen in part for having a long-range hyperdrive - we just don't know.