Wow ! You have a lot of runtimes !

With ShaderWorks, you can add all runtimes located in one folder. So if you have an "Environnement" folder containing all the environnements runtime, you could add all them at once.

But... this is a really easy thing to code. If the above trick isn't sufficient, I could do a "Library Manager" module to my ShaderWorks, that would allow to select your LibararyPrefs file.

But, for now, you won't find a Python solution (or I don't know it). The LibraryPrefs is loaded at startup and, even if it's modified, it automatically replace the modified file with the original one.