FYI everyone: THERE IS A VERY EASY FIX! I was attempting this convoluted method of making it work and I made a much simpler discovery!
If you have multiple drives, and the drive you are installing Windows on will not have any other OS files on it, JUST SET IT UP AS MBR!
With disk utility, instead of playing around with the partitions on the drive, just select the drive on the left side and create a single exFat partition. Disk Utility will make it MBR for you. It's really very simple. When you get into the Windows OS install, format the drive NTFS from exFat (Since Apple doesn't support NTFS in DiskUtility. I don't blame them on this - it would cause them to have to pay licensing fees to Microsoft. Booooo!)
You only need the goofy hybrid configuration if you are using multiple OS'es on the same drive.
So, for instance, I have my MacPro 1,1 booting Window 10x 64bit and MacOS 7.5. I had MacOS 10.11 on this but an update wiped out boot.efs (another topic all together really). Since then for some reason I've never been able to boot my MacPro on an unsupported OS. I think Apple did something to the firmware in the latest OS that prevents MacPro 1,1 from using unsupported MacOS'es. That's why I pursued Windows, because I'm not ready to pronounce this hardware investment dead. Whether they did or did not mess with my system, I have grown tired of their ARBITRARY forced hardware upgrade simply because they're too lazy to support 32bit EFI in their later OS'es. It's been proven that it's not a limiting factor as Piker and others have developed boot.efi files that "thunk" the 64bit commands to the 32bit EFI. Don't ask me how it works but it does, and frankly it's criminal that Apple has not allowed more modern OS'es on their original MacPro's. Just goes to show you that it really is all about the almighty $$ with them, despite all their claims to be more interested in the customer than Microsoft and others. At least Microsoft keeps making sure they build-in compatibility layers for former hardware technologies.
If you read this through, you might detect a bit of hostility towards Apple. It's because I am not terribly wealthy and have loved Apple tech, even though being a Windows System Admin. But when they pull crap like this, it really burns me up. After all, MacPro systems are VERY EXPENSIVE!
So - for all those fellow MacPro users and others who have been abandoned by Microsoft - If you use a full drive for bootcamp, you CAN USE MBR formatted partitions with Windows 7, 8, and 10. It's a whole lot easier, and there is no disadvantage unless you can't use the full drive for Windows.
Happy Computing! OOPS(Update.... make sure to keep the name "BOOTCAMP" on the drive when using Disk Utility to make it exFat!)