After looking at your problem and reading some responses' I had to respond as well.
I have had almost the same prob on the back of my Boler
This what I did unfortunately no pics, but I try my best to keep it simple.
First I ground down the inside area around the break with a 36 grit disc on a angle grinder. Then shaped cardboard to the exterior of the body making sure the curve was at least as sharp as the body contour and adhered it with packing tape to the body exterior.
Applied a couple 3 layers of glas directly to the body and cardboard and let set overnight.
Then ground off the cardboard, roughened up the glas I applied and took off the gel coat a couple of inches around the injury. Then applied a couple coats of glas and let set overnight.
The next day ground off excess roughed up the glas and finished with bondo and paint.
In your case if you don't get the curve perfect add more glas to the side that needs it.
Have you any experience with glas?