Looking to upgrade my old 150 dollar fish finder. I have a 16' G3 Jon that I fish mostly trolling motor only water so looking to mount unit up front on trolling motor. Should I go all in with a unit that does both?? Will side imaging work up front on trolling motor?? What speed do I need to be going for side to work?? Was going to go with a down image unit but was thinking do I bite the bullet money wise and get the best of both? Thanks for any thoughts.