with the variable speed, you can adjust your trolling speed much better, probably by 1/10 mph so it would work well for you. the foot control should have a round knob with 1-10 on it, and you can set your prop rpm's with it, or the remote if it has one. You will need an accurate gps to help monitor your speed. The speed control would work similar to the volume control on a radio, you can adjust the speed just a "hair" if needed.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.