I thought that adding it would be a good way to get the note to the player that starts the quest for my mod but is it going to cause any problems? All I am doing is adding another "Here got a note for you" to it. or should I make my own courier?
I did the same thing with my mod and I havnt noticed any problems. The way I did it was by following the tutorial, then when he tells you to add to an existing dialogue, I right clicked pressed copy, then set my own conditions
Granted, I havnt fully tested it with a full play through. But in theory if you set it up right it shouldn't interfere with the rest of the couriers jobs. As you already touched upon though, making your own courier pretty much guarantees no future problems