I would fix the hood to the car, with intended Dzus clips or fasteners. If shape is still not correct you can either force down with weights or even use a long self tapping screws.


Then apply heat to the hood with a hot air gun, just get the hood warm, you don't need to get so hot that it removes or burns the paint.

You will have more success with a newer glassed hood than an old one, as glass is still malleable for a while. After heating, leave hood in place for a couple of days to settle. Assuming hood is maintaining the shape you want, you can glass in some supports.

Carbon fibre (CF) hoods are great, just ensure the mould which the CF hood is to be taken from, fits your car perfectly, as CF does not move, has zero flexibility, unless it paper thin. . .