Ok so, when a mod selector comes out, download it and look at the mods folder.
There should be a ZIP file labeled somthing along the lines of auto-neuxs.
Open it up and you'll see an XML file, and multiple 14.1.0_autoNexus_%.txt files.
Really doesn't matter which, but open one of them. If you opened the 30% one, somewhere in the file there will be a ".3" jumbled in with the code, which is the math used to autonexus. So just change it to .5 save, and open the selector. It will still appear in the selector as the original % but when you build it will be 50%! cheers.