SI on the TM is a valid option as long as one realizes that turning the TM quickly will skew the new SI data being plotted at the top of the SI image... (It doesn't change the SI history data farther down the SI image that has already been plotted in the SI image) ...

Keeping the TM movements slow (and preferably with the boat tracking straight ahead) when needing to discern structure/fish is the goal ...

And then plan the TM movement when there's nothing coming into the new SI data (at the top of the screen) that needs to be studied ...

Rickie