You can spend thousands on the equipment; but transducer placement can render it useless.
If memory serves me correctly, the side scan transducer is mounted a bit lower than the regular "skimmer" transducer for the fish finder. They also have to be a foot or more apart to work properly.
You might consider mounting a starboard material plate to the stern so you can adjust the transducers without drilling multiple holes in the transom.
I do believe the side scan must be mounted on the transom; but the fish finder transducer can be fitted to shoot "thru hull". You can even buy better transducers like "airman" for the fish finder.
Even if you decide to do it yourself, get an opinion from a professional. If you purchase from Jim at BOE; I'm sure he would give you some good suggestions.
5th
__________________
|