When I went on my scenic trip to Colonia about a year ago, I only mapped truly valuable bodies, terraformables, ELWs, AW, WW, and their moons or binary partners. And not for all of those would I make a >200kls trip to a body orbiting a secondary star. Very rarely did I map gas giants, normal HMC or ice worlds. Basically only when I was after certain elements for synthesis, or geo or bio signals etc worth landing. But yes, class 2 GGs should be worth a little more than the others.

About the boxy star clusters, that's an artefact of the galaxy generation, you will come across more of those cube sectors.

About the Codex, you know, after a few weeks just hopping and scanning, things may get rather dull. So I decided to try to fill my codex for the respective regions I am passing as far as possible without visiting the same system as the CMDR first reporting it. And even though I restarted Elite for that trip about half a year after the Codex was launched, I still managed to get my (first) "Reported by" entry for a stellar body - seem to remember it was a fairly rare G Supergiant. so now everybody can see that my CMDR was first to find that kind of star in that region whoohoo
I guess now a year later that might be even harder to achieve wink