Hey Scott, I found this
on youtube its a video of a guy selling his pelican bass raider but in it he shows his transom which is reinforced with an aluminum cross bar and bracket arms attached to the boat pretty sturdy, I may do this or do a wood contraption that will fit over the transom and rest of the stern so i can reinforce and attach other things. I will be using a 3.5 hp and I know it will flex.
Side topic for rudders, I copied someone and cut a piece of 1/4" plexiglass about 4"x12" and drilled holes on the bottom and side and zip tied to my trolling motor which I place in the back, my reasoning is due to waves and wind I like to have as much weight in back to prevent water from coming over the bow. After I get my 3.5hp on I will move the trolling motor to the front and will work on designing a light weight splash skirt to prevent water from coming in the boat when moving at a good speed.