Update:
Got Windows to install in the GPT format by forcing the "UEFI" DVD drive to boot instead of the "Location 1" DVD drive. Never really knew what the difference was before, mustv'e had the UEFI drive set on first by default the first time I installed Windows when I built the computer. I installed it in two ways, but both creating the same end result, one way by booting as stated before and letting Windows PE automatically create the necessary partitions (UFI, MSR, primary) and installing Windows. Second was in using that document you linked for me to use and manually created said partitions by commands in "diskpart". Each attempt did successfully install about 80% of Windows, AND created the "Windows Boot Manager" boot option (which is a VERY good sign :joy
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The only problem is when it needed to restart after the "Installing Updates" phase and before it went into the "Completing Installation" phase, it came up with an error :glare::
"Windows could not finish configuring the system. To attempt to resume configuration, restart the computer."
Now that I think of it, I did have the DVD in the drive, but it shouldn't matter.
Installed the regular BIOS friendly Windows and got here, but noticed that then "Windows Boot Manager" was still included in the boot options, so something must still be in NVRAM regarding the UFI portion of the Windows installation.
Now I do appreciate the help because this is encroaching entirely on Windows territory, but if anyone happens to know what that error message (as stated above) could mean and what could be done about it, I'd appreciate it, because that seems to be the last hurdle to get over, then everything will completely be okay again it seems.