Convert flash drive for Windows 8.1 bootcamp installation from mbr to gpt

Trying to run Windows 8.1 pro x64 on my mid 2010 15" macbook pro. Get stuck during bootcamp installation in Windows because my partition table isn't compatible (MBR but needs to be GPT). My hard drive seems to be Logical partitions/volume etc, while my flash drive was formatted into MBR seemingly by bootcamp, or otherwise not altered into the GPT like it maybe should have.

Generally followed this guide http://www.howtogeek.com/186907/how-to-install-windows-on-a-mac-with-boot-camp/

Steps I took:

Had to use terminal/Xcode to edit info.plist from bootcamp to allow flash drive installation through bootcamp on my mac (removed the "pre" method).

With all three bootcamp options selected, managed to partition the drive

When restarted, my computer had black screen with "no bootable device found".

Restarted again, holding alt/option

Flash drive was now available as one of two options (the other being my standard mac drive)

Windows Setup loaded. Selected language/imputed key/select version etc.

Here is the strange part, the division of the disk does not include "bootcamp" anywhere in the title (like it should according to the guide), and is about 10gb smaller than my partition (assume this is a normal result of windows installation/os files etc). When I try to format the partition, it says I can't, and explains that I can't use MBR, need to use GPT.

Attempted to rewrite disk with Shift F10 Diskpart, list disk, etc, but here it shows drive 0, 1, and 2, (rather than drive 0 partition 1,2,3,4, with 4 being my bootcamp I think). This seems to be a method for installing windows on a windows pc, and I didn't go through with it because I didn't want to loose my mac os yet.

I am not proficient with coding/terminal use, and don't know if there is an option to list partitions etc, so I'm stuck. I can backup my mac and potentially change my partition table etc, but I feel like restoring with time machine would then wipe my existing partition. Is there a workaround I could use? Is there a specific sequence of backups/restores that would work? I'm also okay with manually drag and dropping the files I want back onto a clean slate computer if necessary. Or would simply buying and burning a disc with windows save myself the hassle? Please advise.

Sorry for long question, wanted to get info out right away. Can include more if necessary. Thank you all for your time.