To change the droprate for R6, R7, R8 and Kjarr weapons, place the `em117_grade_lot.em117glt` file in `steamapps\common\Monster Hunter World\nativePC\common\equip` 
  
If the nativePC folder or any necessary subfolders don't exist, create them.  
  
Only the file named `em117_grade_lot.em117glt` will be read by the game, so you can leave the application in `nativePC\common\equip` and create and name multiple files for your own presets, switching them as desired.