The main issue you'll run in to with these are the low resolution screen. Even with a decent transducer you probably won't see much with the screen. I recently tried out HB's Piranhamax 4DI and it was like this.

I mean, you'll see basic depth, bottom contour, and a fish if it's big enough.

Youd be be better off with a Helix 5 and mount the transducer on a board