That works well. When you first try to open the .out file by double-clicking in the explorer, you get a box prompting you for what program to use to open the file, since .out isn't registered to anything.

Whatever word processor you choose, you'll want to make sure you have checked the box "Always use this program to open this file". That force Windows to assign .out files to the word processor you choose for the future. You can also fill in the text box at the upper portion of the window which will show up in the type field in an explorer list (As happens now with CAESAR_II_Input for ._A files).