Slow to me when I spider rigged was to cut the tm on long enough to get the boat moving then shut it off and drift until the boat completely stopped moving. Then cut it on again, off again, etc.

To be more specific to your question.....a lot of us use a tm which has I-pilot. Th remote keeps you at a speed by setting it on "cruise control". Others use their GPS built into their depth finders and have it mounted on the front of the boat with the transducer mounted onto the tm shaft. All that aint necessary but it's nice to have.