Storage of Fibre glass is difficult at the best of times. Storage of an Aristocat bonnet is more than difficult because of it's shape. Store it on it's back and the wings spread. Store it as it would fit on the car and the wings spread. In addition when you have installed the body on to the chassis the bonnet might not have the same contour as the scuttle.
The sketch below shows how to store, how to change the shape and how to permanently fix the shape.
1] Rope the wings having drilled 1/8" dia hole in the return and wind the rope loop until the correct width is obtained. Beware of pulling to tightly or the centre will want to "hump".
2] When the bonnet is installed the rope can loosened or tightened to get the correct fit. Lock this shape by installing a copper tube brace between the wings to prevent the "humping" brace the centre of the bonnet with fibre and resin over half a cardboard tube.
When storing the front and rear body sections before mounting them on the chassis make sure they are standing on end. That is with the front light apertures pointing skywards and tail of the rear section pointing skywards. Once again rope or restrain the wings from spreading outwards.
Fibre glass can take a very long time to completely cure. Make sure you control the shape.