Many thanks for the quick response. Everyone else feel free to chime in with other ideas.
The head liner is in good condition everywhere except the back, where heads have previously rubbed.
It also doesn't appear to have had rear seat belts, as I haven't found a place they should have been mounted to.
The European version with 1.6 engine got a 4-speed from '78 to '80, from '80-'82 they got 5-speeds standard. The interesting thing is that mine is the earlier version and it has a 5-speed. It could be that the transmission was replaced along with the engine, which the previous owner told me he had had replaced. At least, he said he had the block replaced.
My engine is a SOHC 1.6l 55kw, with a stock CR of 8.6:1 and points ignition.
As for the template, I used the second picture I posted and came up with the pictures below. The problem is that the car doesn't have one section of the roof that is the highest; it is all level. So does that mean I should use the center of the roof as the reference, or just fit the template to the car however makes the Kammback easier to build?