I have a pr of Garmin 73sv graphs on my boat. 1 mted at console with a transom mt transducer and the other mted at bow with a TM mted transducer. My boat idling spd with big motor is 3-3.25mph. The scroll spd options are Fast, Med, Slow, Ultrascroll and auto. I would like objects to show immediately after transducer passes over. What spd scroll would you recommend. I use the bow mted graph to "see" directly below transducer real time. Spd with trolling motor is less than 1 mph. What scroll spd should this graph be set on. Thank you!