I've gone through several iterations of my transducer mount on the PA and here is my latest which I am very pleased with after about 5 trips with this configuration. The side imaging feature does not allow fitting the transducer into the Hobie Lowrance Ready hole which is an excellent feature IMO if you can use it, so my options were side mount or rear mount. I went with the rear mount with some apprehension of damage but most of my fears have been reduced with about a year's use in this position. The most recent change has been substiuting the Humminbird standard transducer mount which is fairly large and therefore results in drag and an audible noise while the kayak is underway. That setup also had the ram 4" extension in the water as well creating more drag and noise. I used a piece of plastic cut from leftover scraps of a PVC fencing project to create a fairly clean extension between the ram mount and the transducer. I've basically eliminated the noise I could hear before and cut the drag of the mount by 83% eliminating 1 pedal stroke for every 300.
Such an approach could work on side TDA mounts as well.
This is in operating position and I usually just leave it here at all times - even during travel (on a trailer).
The ram extension gives me much flexibility if I wanted to give the xdcr more depth.....but I found it not necessary for my application. The ball mounts also allow the xdcr to move if it were to make a significant impact eliminating the concern for damage. But the ram mount is still tight enough to prevent movement during normal operations.
If you felt it was necessary to move the xdcr up for travel or portaging kayak, etc., it is possible to move it above the boat as shown below:
Maybe this will give you some extra ideas or options on mounting with a eye towards eliminating drag and noise. Tight lines.
P.S. - all nuts/bolts are stainless steel and nylock nuts.