Welded the three pieces that make up the front together and was quite happy with the look.
As always, I checked the profile at the same points on each side to make sure it was even.
Well it is nowhere near the same this time!
I wheeled it to match the other side using a rubber band on the upper wheel to make it go quicker. Looked good matching many points left to right.
But all was not well when I placed it back on the cab to check fitment!
Not sure if it was because I used the rubber band when wheeling as it only bends rather than stretching to change shape?
Sits up a lot as should only have a slight rise. Tried wheeling more without the rubber but was having some trouble on my own with it this long and keeping it level when running it through.
Cut it right in half down the middle of my nice centre crease.

Even in half you can see how much curve it has. To my mind it needs to be stretched along the bottom to pull it down.
I hadn't been able to wheel right up to the flange as the centre of the lower anvil/wheel is away from it. So tilted the lower so I could get up to the edge to stretch that area to see if that would help.
I did some hammering along the edge over the welding bench as well and it is getting the desired result. The left one in the picture is the one worked.
Placed it also over an original roof panel to see the difference. I have left out the more vertical section at the gutter line as think at the front the softer slope looks better.
Was not sure what I would do with my crease as it was completely wheeled out and would fit in my bead roller anymore either. I didn't want to cut off the overlap, weld it, and then stretch it once again to put the crease back by hand. So just put the shape back in by hand over the edge of the bench while still in two halves.
Got the shape back and did the other side as well which had to match exactly.
So welded it together again while clamped down to the gutter and then took it off to planish the panel.
So the height is one inch shorter across the front and a softer curve to it.
Here is a scrap piece of bonnet with its centre crease to get an idea of how it will look together.
I also wheeled a bit more crown into the rear as thought it was a little too flat and now matches the front as well. Still 1.5" less than stock in height overall at the sides and 2" lower in the middle.