I,d suggest the following.....
position bonnet on top of nose which determines the precise position of the scuttle.
remove nose, bonnet, scuttle...
fit side panels...D9 & D10 are useful to determine where the side panels meet the rear tub. ( would suggest that all pedal box fitment is complete, otherwise you,ll end up with your head in the footwell with legs sticking up in the air
, been there
then fit rear tub
then fit rear wings to rear tub ( my tub is rivnutted to the chassis & wings bolted to the tub so that if needed I can remove it all in one go )
then refit the nose, bonnet & scuttle.
Depending where you have welded SW1 to the chassis you may need to cut a little notch out of the scuttle to allow it to sit on top of the side panel/chassis top rail.
edit..... no need to remove any of the side panel top edge where the scuttle is, scuttle is fine to sit on top of it, you "might" need to remove some of the top edge of the side panels to allow a good fit of the nose so that the nose sits directly on top of the chassis rails.