...and I suppose that could be a bit trickier than with transom-mount transducers? I'm not sure how you'd try different spots.
In the past, for my transom-mounts, I used a suction cup to move around the transducer and find a good spot on my boat. Now I always have a solid read on bottom up to 20-ish mph and, depending on bottom hardness, up to 35 mph.