Hi,
My scroll speed setting is a compromise between seeing my lure movement versus how much "history" I want to see on the screen (you decide). Remember your lure will be a straight line (versus time) if not moved in the water column. As a brag I have tracked a #10 Gil Pill (local bait - I think it is 1/64 th oz) at the bottom of a 30 ft water column - no problem! Some Ice Fishing tips I could pass on would be like, 1) keep your back light intensity as low as you can - most of your battery consumption is taken up in the lighting NOT the electronics, 2) on the full screen run with RTS set to wide - you will see returns that will not even show up on the graph screen, and 3) move up to a 9AH battery - I can get easily 12 hours running time (again if I manage my backlight intensity) - also bring along extra batteries for longer stretches on the "water".
Have fun,
Roger