Yellow_78: I'd be interested to know what you think as well. I did the same install last week on my new 2017 hull with the Helix 7 SI and Berley Pro plate. I only have one day on the water with the set up but tons and tons of experience with Hobie Pro Anglers and Humminbird electronics. In deeper water the 2D sonar works fairly well with the exception of up near the surface where there is a solid return layer to about 3ft down. The down imaging seems to have interference as obvious fish returns from the 2D sonar picture are very hard to see even with some serious tweaking of the settings. Also bottom structure isn't very well defined on down imaging like it is on my previous units with the transducer over the side on a transducer deployment arm. Side imaging doesn't show much of anything regardless of what I do with the settings. The depth readings and temp readings seem to work flawlessly.
In shallow water (7ft or less) the 2D sonar is pretty unusable. The returns cover the entire screen and there's no definitive bottom. Down Imaging is the same in shallow water as it is in deep water. Side imaging continues to show nothing even in areas that I know have bottom structure.
I'm heading to another lake this weekend that I am extremely familiar with and will see what I can find. Luckily my girlfriend fishes from my older hull with an 859ci HD DI unit on there and the transducer is over the side on a deployment arm so I have something to compare pictures with in a side by side format.
I'd love to hear what others think of their Humminbird SI units with the Berley Pro transducer mounts. Screen shots would be a bonus. I'll make sure to get some this weekend as well to post up to better explain what I'm seeing (or not seeing

).