Anybody Using a Transom Transducer on a Medium Size Boat?

During our one-week covid crisis cruise of 2020, we resolved (as in I talked Jan into the idea) to upgrade the electronics on our boat. The newest thing aboard is a 2001 model Garmin GPS. That's the easiest thing to replace, and the new plotter/sounder display will also be the "destination" for the signals from the new radar, autopilot, etc. For a few reasons, I thought it made sense to start with the main display.

Spousal OK in hand, I wasted no time in taking the first step. Found a brand new, deluxe, 12" Raymarine unit, still in the box, for about $1000 less than West Marine and $700 less than Amazon. {little dealer down in South Carolina says he has one more at that price}. It won't be too hard to yard out the old, surface mounted chartplotter and wire in the new one. (Toying with the idea of moving the old electronics up to the flybridge, where I currently have a compass and a depth sounder.).

The Raymarine included a "transom mount" transducer.  My current transducer is mounted through-hull near the keel. I'm going to guess it's unlikely the old transducer would "talk" to the new display, so I'll almost certainly need a new transducer.

I normally associate a transom-mounted transducer with smaller boats.  Speed isn't going to be an issue ("Dear Prudence" is a slow movin' old girl. She thinks 11-knots would be like traveling at the speed of light).  The unit itself would slip down between the swim step and the transom, so it would be reasonably well protected. I like the idea that if I am going to put a new "hole" in the boat it will be above the waterline.

So is anybody using a transom-mounted transducer on medium-size boat (40-feet) like "Dear Prudence". If so, how has that worked out? Anything I should watch out for?

Funny "WARNING" packed with the transducer. "Please carefully read instructions before drilling any holes in boat." You think?