[JohnB]

If your using poly, I agree with GradySailfish, if your using epoxy, it would probably work ok, I am just am repeating what I heard from guys that know epoxy, and my own experience.
As far a the big epoxy vs poly, when it comes to transom, generally, people are hanging heavier and more powerful engines, on brackets, off the back of these boats. IMHO, you need to beef up the design and/or materials to compensate for this.