So I've cut out the original roof frame and supports ready to weld-in the Falcon bonnet.
I need to make new roof supports.
I started with lengths of 1/2" aluminium tube which were bent to the correct roof contours (around an old wheel!)
Welded 80mm apart with 2mm mount brackets.
This will be bolted to brackets welded between the 'B' pillars and the rear window frames.
But it's only a start. If the roof support ends up looking like the picture in my head it will blow you away!