Let's make sure we are on the same page here.
If you have a bracket like this.
Do Not mount the X-ducer in it. Water roll's up and is disturbed in that area. You will only get a decent pix when the boat is at rest.
Sorry, I reread. You want to mount a transom mount X-ducer. You can do that, but it sure looks bad with the cable run all around the bracket.
Why don't you mount a B-60 thru hull like reelescape1 showed in the first place?
It's a nice unit, works VERY well and makes a clean install. I've put 2 of them in different boats.