This is a very simple mod, I went through the Spectral Assassin\'s audio files and changed the reset timers to play the annoying random crap he spews constantly once a day instead of every 5 god damn seconds.
Download Say it ONCE to make him only voice his random chatter dialog one time EVER instead of less often.

To install simply extract it to your Data folder

The only requirement is the latest version of Skyrim

May no longer work, Its been a while and I no longer have creator's studio installed.  I might someday get the time to fix it, but don't hold your breath.