I just purchased a Humminbird HELIX 9 CHIRP DI GPS G2N. I will need to swap out the transducer with Humminbird to a trolling motor version and I noticed there are 2 to choose from. One is a XTM 9 DI 25 T and the other is a XTM 9 WIDE DI 20 T. It will be used while spider rigging for crappie and I won't be in extremely deep water. Any info I need to make this decision easier would be greatly appreciated.