I've got an Ultrex Quest and I can adjust the settings through my Helix depthfinder. I have not messed with the scale settings, but Dutch has changed his because he was having an issue with the boat holding in wind (I think that was why he changed the settings), @Dutch.
Here's the official explanation:
Trolling motor performance can be impacted by factors including, but not limited to, wind, water conditions, boat specifications, battery health, wiring, etc. Boat Scale provides a method of adjusting how the trolling motor will perform to account for these and other variables. The Minn Kota trolling motor comes from the factory with Boat Scale set to zero. Boat Scale can be adjusted up (+2) or down (-2) to increase or decrease how the motor control software applies power while using a navigation mode like Spot-Lock. An example showing the need to reduce Boat Scale would be while using Spot-Lock and the motor is over-correcting or making frequent adjustments. In this case, try reducing Boat Scale to -1 to reduce this behavior. If the behavior continues, reduce Boat Scale to -2. An example showing the need to increase Boat Scale while using Spot-Lock would be the motor is drifting away from its target location frequently or needs help to make corrections. Try increasing Boat Scale to +1 to help improve the trolling motor accuracy in this case. If the behavior continues, increase Boat Scale to +2.