But right now that makes me worry about the hatches. If i cut them out now, they won't bent with the rest of the deck when I put it on the hull. And then the hatches will not fit. Any good advices on this?

Palle Dam
Denmark

Correct!but you may be lucky.
You can adjust this wrong curve in the end by removing some glass from the inside surface of the hatch to the point where you can reshape with a little over bend, for when it relaxes, and locking that new curve with some new glass on the inside surface.
I don't cut my hatches until the whole assy is together.I glass the outside of the deck after it is glued to the hull.This avoids this potential issue [to some extent].I have to do other stuff because of this but I like doing preparation and foresight helps.
cheers,