MBR2GPT Disk layout validation failed

macsrweDon't think of the process as how you described. Think of simply decreasing the volume size.
Read my instructions again. The instructions don't get specific about using Disk Management since all those who had posted were well versed with that portion, apparently. You're really not "reversing" the instructions. You are simply using the same instructions to reduce the volume and allow Windows to determine the "where" to move things around.

Open Disk Management (use the search bar in Windows - it will appear as "Create and format hard disk partitions" - click and look around to get used to where things are, labels, options, etc.
When you're comfortable that you have at least an idea of what you are going to do, then "select" (click on) the volume you want to edit.

Since you've already determined where you need space, you are going to reduce the volume by the amount you have determined using the "log" information where it states how much the volume size is over - or, too close to ?

Right click on the volume that needs to be reduced in size. You will have an option appear in the list from your right click where you can click on "Shrink Volume".

When you click on that another window will appear. In that window you will see the size of the volume and a field you can change the numbers (size) of the volume. Change that number to comply with what your "log" said (something like "too close to XX").

There is a calculation between the size of the volume and what the log says it should be. In your case, your log will state something like "...too close to beginning of disk. Should begin at offset X or more, found at X.
So you want to calculate the difference between "Should begin..." and "...found at..."
The difference is the amount you will "shrink" the volume (change the numbers in "Shrink Volume") so that the volume matches what the log is telling you. If you make the volume slightly smaller than recommended, that's better - just don't go more than a few digits smaller than recommended (unless you have lot of space on the drive that's not used).

When you have manually changed the volume numbers, click "Shrink" in the little window and Windows will do the work.

When that is completed, run the MBR2GPT test again. You should see that the test is happy with the volume at that point.