I may have only caught 2 or 3 sandbass in my time as a fly fisherman
but I don't even so much as own a sinking line. Think about how deep the creek is you are going to be targeting them in especially when they get really pressured I like having the floating line to hold my fly line above the fish as to not spook them. I do have a buddy that likes to use sink tip though. If you are really needing to get a lot deeper you might think about the concept of a sink tip as well so that the main running section of your line is not running right down the middle of the school. Of course I have seen it when you could walk out there and kick them with your boot back up and cast into them again and they all eat just fine.