I have the 45" on a 721 and fish rayburn and toledo all the time without an issue. As far as turning spot lock up and down, you can. There is a setting called boat scale. Most bass boats like a +1 or +2 setting. If your getting blown off the spot and it's correcting real hard then that setting is off. Once that's set right the only time it will act a little crazy is when you first turn it on and it sets itself