I have two sinking tip lines from Scientific American and they both have bright floating sections with only the sinking tip part being dark. Its much easier to see than a straight dark line. I concentrate on the where the visible bright yellow line starts . That way I don't need an indicator. Still and all most strikes are detected by feel. I use many different types of retrieve untill I find what the fish are interested in that particular day.
Don't make the mistake of re-casting to soon as I find that often fish grab the fly as it approaches the boat or shore. I find most strikes are within 20 feet of me. With a sinking line I sometimes anchor and let the line sink straight down beneith the boat. I inch the fly toward the surface slowly, the strike when it comes is often near the surface. You have to be very quiet in the boat for this type of fishing.