Depending on your Home / Favorite Water a standard Floating Weight Forward Fly Line will do you fine. Depth Charging for Silvers/Reds is not a consistant method of fly fishing. Sink Tips, Full Sink Lines haev there place just not needed for fishing most Salmon. There are those who will not agree with that statement so be it.
Example: WFF, Loop Connectors with Braided Loop System will allow you to change your line from Floating to Sink Tip in seconds. Best bang for the buck Weight Forward Floating with a series of Sink Tips made for diffent depths of fishing i.e. a 12, 24, 36, and 48 inch Braided Loop Sinking Line leaders attached to the end of your WFF Line.
I like to use a sink tip for reds. Not to say that a floating line won't do the trick, its just that I seem to do better swinging the fly with a sink tip. I use a Reo Six foot sink tip with the six inch per second sink rate.
It is all what you are comfortable with. Line control is the key. If you can have better line control with a floating line, stick with it. If you can have good line control with a sink tip, use a sink tip.