Oh how I wished this method worked out for me. After trying multiple techniques to upgrade to VC without bricking, I had given up and downgraded back to V9 with Lego Rom. Everything was in working order, could turn on and off, plug the phone in, etc. I was happy but frustrated that I couldn't get a stable VC on my phone.
Then I saw this thread, which incorporated a few things I had tried before, including a straight jump to VC from a rooted, custom recovery and custom ROM V9. The success of others gave me the confidence to try it. I nandroided my Lego Rom setup and followed the directions. Everything was great, I installed VC through the LG tool, let it reboot, and then went into recovery (dreslisdee's 1.2 version). I flashed ThunderRom 1.7 as Lego doesn't fully work with VC. Everything was golden as of last night.
Then this morning I woke up and the phone was fully charged. No brick overnight through charging like I had happen before. Then I unplugged it and turned it on. Brick! I pulled the battery and was able to get to recovery. I turned it off and tried to turn it on again. Brick!
I knew I could get back to V9 by force flashing through KP500. So I did that, custom recovery was still there, I wiped everything and restored my Lego ROM nandroid. Back to square one.
I am typing this all to say that while I am ecstatic that this technique has worked for others, it didn't work for me, and I am quit sure that I followed the directions correctly. I am no longer frustrated, just resigned. One day someone will come up with a foolproof method, or Sprint/LG will realize what a mess was created by VC and release an update.