A request was made for the OP to post a photo of the hood as it is today, this would help to better understand just how much the hood would need to move. Many an AAR hood suffered the fate of being ripped from its backing structure when someone would forget to install the hood pins, the subsequent repair often leaves these hoods in far worse shape than they would have left the factory.

I've worked pretty extensively with composites of different types and cut my teeth as a tool engineer. Early composites were not well understood, things like CTE, shrink factor and spring-in were not well understood or accounted for in tooling. So the factory hood wasn't as perfect as you may be able to achieve today.

To your point, I have never tried to simply add weight to a hood in an attempt to flatten curvature. I suspect only the smallest of movement will be achieved and the hood will quickly revert to its original shape. That said I would encourage the OP to give your suggestion a try as it is a much easier, less intrusive fix that anyone can perform.