From the Launcher, check the drop down, will be an option that says 1-turn recruitment, just select that. Keep in mind, that with 1-turn recruitment, none of the scripts will work.
As to compatibility within the current game, I don't know, since 0-turn is mod foldered, and 1-turn is not, I doubt it is, but you can always try it and find out. (Just make sure you don't save it after you switched it)
Edit:
Not sure if this has been mentioned before, but I noticed that all traits through the Cursus Honorum and also the military career ones, do not appear on the side nofitication if the character gains a new trait when you start the beginning of a turn. Not sure if that's an easy fix, or a mistake (as I do a know a patch is coming to fix some of the glitchy traits), but never the less I thought I would mention that.