Please help convert US990 KDZ to TOT or BIN/is LS990 same partition layout?

I have royally bricked my US990, any time it boots up it goes to fastboot, including trying to enter download or recovery mode. Also, it's not rooted (I was trying to return to stock), so if I try to erase or flash aboot/laf/recovery, it just hangs. So I'm trying to follow this guide to recover it, but I need a TOT or BIN file to use it, and so far all I've been able to find are KDZ versions of the US990 firmware. I've tried following a couple guides to convert them to a BIN, but so far haven't had much luck. The .cab files LGExtract creates aren't valid, neither 7zip nor cabextract can open them, and P970 ROM CONVERTER doesn't work either. Most versions of WindowsLGFirmwareExtract crash when trying to extract individual BINs from the DZ, although the one included with ImagePrepGUI works. So I now have individual BINs, but no partition.txt

I have several different options for KDZs to work from, I'm trying to use US99023a, which I believe is the latest Lollipop update. I also have the LS990 ZVA tot, which I've extracted. It looks like the bin/img files from the kdz are the same as the mbn's that BoardDiag produces, is that right? And can I use the ZVA partitions.txt with the files from the US99023a kdz to get this thing running again? Or, if I try it and it fails, will it be any worse off than it is right now?