I built a stitch and glue and noticed that after gluing the inside I noticed the stern was out of plumb. Not sure if it carried much below the waterline. I took a hand saw and cut down the center seam at the stern and epoxied it up. It was fine and a little heavier.
Why not remove a rear portion of the deck, say two feet. Make a nice cut because it will be reset. Then recut the stern and re glue straight?
Agree with the others on ethics but why make a planter yet? You could paint the bow and stern in a bright color similar to an Epic and it would look fine.
I have lines, levels, lasers and a cautious eye prior to setting the ends. I prefer to epoxy each end separate from the main to avoid a twist or problem.
Years ago I had a flat spot on one side of a stern where I should not have. ( 19' Patuxent) On that one I used fairing filler and painted and it worked fine.
Is it a hollow or a twist at the stern?