If there is no transducer block, I would certainly put one on before you add another transducer. Since it is a new boat, you may change a few times over the years. Not so many holes drilled in the hull that way.
Have had zero issues with floaters , and all in very bad frost heaves/ ground moving areas. I believe they are 13,10 and 4 years old. But then again, I certainly do not know it all. MAYBE I can learn something?
You will save money, and will also like the floating deck idea. Not that hard to build. Your handy enough (from other pictures i have seen ) to make it come out strong and just the way YOU like and want it.