Using a sink-tip line for smallie streams would all depend on if I'm using weighted flies and how fast the current is flowing.
If the water's high and fast, then yes, I would use a sink-tip. I'm not sure of the sink rate, but it's a Teeny WF7ST. This line has a 7 foot sink-tip. I keep it on an extra spool so it's ready if I need it when I get to the water and find it's running fast.
Otherwise, I just use a standard WF7F line by SA. Most of my streamers and nymphs for smallies are weighted, so this line works just fine. Plus I can just cut the fly off and tie on a topwater without having to switch lines.