Worked mostly as advertised! Thank you, Terry!
Since my
LG H-320 came with the
V10g-EUR-XX firmware, I tried to downgrade - not a single of the other rootable firmware from the posted links was stable (stuff kept crashing) so I reverted back to the original V10g.
I still decided to try this method, and lo and behold, my phone is now rooted!
I actually used
NewKingroot v4.82 (release from 09/03/2016), available on the XDA Developers' forums, to root my LG. Downloaded the compressed file "Rootin", followed instructions, and was finally getting some positive response from the commands.
Lines 8 through 20 in
step 7 returned me with "no such file or directory", but from the looks of it, those commands might be messing with Kingroot files that no longer exist in the version I used... I'd guess.
Disheartened but not hopeless, I kept going...
...and tadaa!
I used my IMEI on the
page the OP shared in the downgrading guide, and the
V10g I used is now available there (It's the TM3/TMN_MEO one from Portugal.
Good luck!