Removing The Test Mode Watermark?

My friend is a coder and he said he has to have the Test Mode on to test some stuff but that he's annoyed by the watermark ...

All good so far, we ran the utility caled My WCP Watermark Editor and removed it successfully. But, later on he changed his display language from English to native and the watermark was back (in the native language). We tried using the My WCP Watermark Editor again but it gave an error every time, no matter what we tried.

It was basically like that; install the REG change to be able to take ownership of files (Take Ownership of a File, Folder, Drive, or Registry Key in Windows 8).

Then copy the shell32.dll.mui from the %WINDIR%System32En-US (or in the native language in my friend's case) and open it with the Resource Hacker (Resource Hacker).

Find a certain string and delete the entry that can be seen in the watermark. Then copy the basebrd.dll.mui from the %WINDIR%BrandingBasebrden-US folder and edit it with the Resource Hacker, find certain string and remove it.

Then overwrite the files with the changed ones (that's why the "take ownership" REG change was needed). After that we uninstalled the REG and rebooted.

After that I run mcbuilder.exe and after a couple of seconds it just closed the CMD screen.

The watermarks are gone - what I'd like to ask is:

Did I do right by running mcbuilder after the reboot or should I do it before?

Is this safe? Is it likely that it could cause any system unstability or whatsoever in the future? Or are we perfectly fine?