wow, pain!!! I got you
to be honest, I own the v400 and I did not know that the KK build for v410 was a TEST OS, whatever it means!
So, for my v400 and for my G2 all I have to do is download the kdz and flash with LG Flash Tool or also use LG Mobile to use the official way to restore, here there's a lot more of work it seems!
My guess is to follow the guide you linked, it seems complete and safe, but before starting the process be sure to have all files and understand what you are going to do; naturally the best place to ask for help is that thread, where OP and others v410 users could help you better..
But yes, pretty sure you'll need the parted file because it seems that the TEST OS format the /data partition (that is the plce where you'll save your photo, videos, application data etc) with a 4 GB space only..
Yes, uninstall King root no problem there..
---------- Post added at 01:11 PM ---------- Previous post was at 12:57 PM ----------
oh forgot to say:
Also before doing all that, be sure to download and install LGMobile Support Tool (here a link
http://www.softpedia.com/get/Mobile-Phone-Tools/Others/LGMobile-Support-Tool.shtml) and know how to enter bootloader, so that in case of disasters you will be able to restore last official Lollipop build!